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Perfectly rich, beautifully cheesy, and deliciously legendary, this Fleming’s potatoes recipe is destined to steal the spotlight. With layers of velvety potatoes, buttery leeks, and a whisper of subtly spicy jalapeños—all in a silky cheese sauce, each bite is pure luxury. Ideally creamy and completely crave-able, one bite of this potato and leek gratin and you’ll forget all about the entree!

“I love potato gratin and your version is absolutely wonderful. I could eat this as a main dish and wouldn’t miss anything else.”

– BRENDA
Action photo of a serving spoon scooping a slice of potato and leek gratin from a casserole dish.

Update: This recipe for au gratin potatoes was originally published in November 2014. I made updates to the article below to include more information about making Fleming’s potatoes at home.

Hi, friends If you’ve ever dined at Fleming’s Steakhouse, you already know the truth: the real star of the dinner show isn’t their filet. And, if you’ve never been, it’s my absolutely pleasure to introduce you to this lusciously delicious twist on classic potato gratin: 

Table of Contents

About these flemings potatoes

Imagine: tender layers of thinly sliced potatoes mingling with mellow, slightly-sweet caramelized leeks, and a whisper of jalapeno pepper heat, bathed in a luscious blend of cream and molten cheese—all baked to bubbling, golden-crust perfection. Honestly, they aren’t just any potatoes. Oh, no, no! These Fleming’s potatoes are a rich, creamy, cheesy fever-dream. Think: steakhouse au gratin potatoes with a major gourmet flavor upgrade. 

Perfect for dinner parties, your holiday table, or simply anytime you want to treat yourself to an unforgettable steakhouse classic, this potato leek gratin is the ULTIMATE side dish. 

If you love rich gratin casseroles, be sure to check out this Brussel sprout au gratin next (it’s seriously THE BEST)!

Why you’ll love this recipe

TL;DR? Get the details below:

  • Flavor Nirvana. Between the savory potatoes, duo of cheeses, buttery-sweet leeks, jalapeño spice, and rich cream there’s ZERO shortage of decadently gourmet flavor.
  • Perfect Texture. Velvety, thin potatoes meet tender veggies, molten cheese, and silky cream to create layers of melt-in-your-mouth texture while the shredded cheeses on top create a beautiful golden crispy crust.
  • Pantry Staples. Basic ingredients transform into a restaurant-worthy side dish.
  • Approachable and Foolproof. I’ve been making this recipe for potato leek gratin for the past 11 years with zero chances of slowing down. Whether it’s your first gratin or your fiftieth, my simple method is forgiving and perfect for any home cook.
  • Customizable Crowd-Favorite. Nix the jalapenos to keep it ki-friendly, use a blend of cheddar and Monterey jack for milder flavor, swap in Yukon golds for a saucier gratin, and more. It’s truly a flexible all-season side dish cozy enough for Sunday dinner and elegant enough for the holidays.
Overhead photo of raw thinly sliced potatoes, sautéed leeks, shredded cheese, fresh thyme, and heavy cream in a large mixing bowl.

Ingredients for potato and leek gratin

Below you’ll find everything you need to make this recipe for Fleming’s potatoes gratin:  

  • Potatoes. In my humble opinion, the best potatoes for au gratin recipes are russet potatoes. They hold their shape beautifully and soak up the luscious sauce like a dream. Just be sure to thinly slice them evenly for even cooking. Substitution: Yukon gold potatoes work too, but your potato casserole will be “soupier” or “saucier”
  • Unsalted Butter. For sauteing the leeks and jalapenos, as well as greasing the casserole dish.
  • Jalapeños. Lend a little bit of savory heat. 
  • Leeks. Add a subtly sweet, mellow onion flavor. Be sure to only use the white and light green parts of the leek. Substitution: Yellow onions work too.
  • Cheeses. I like to use a combination of Colby jack cheese and pepper jack cheese for melty, gooey goodness. Substitution: Any good melty cheese will work here. I personally also love cheddar, gruyere, or Monterey jack; but use what you like. 
  • Garlic. For a touch of punchy aromatic flavor.
  • Heavy Cream. Creates that signature rich white sauce.
  • Salt and Pepper. For overall flavor.

Recipe variations

  • Extra Cheesy. Sprinkle the top of the leek and potato gratin with freshly grated parmesan cheese before serving. I personally never skip this step.
  • Herb Infused. Add rosemary along with the thyme for a more fragrant flavor.
  • Milder Flavor. If you need less heat, skip the jalapenos and use a can of drained mild green chiles instead. Or simply skip them altogether.
  • Bacon Lover’s Dream. Feeding a carnivore? Cook a few slices of bacon and use the fat to sauté the leeks and jalapenos. Then reserve the crispy bacon and garnish the top of the Flemings potatoes with a generous scattering of the crumbled bacon.
  • Homestyle Gratin. For a more classic, home-style gratin flavor, swap the cheeses out for cheddar cheese and parmesan cheese.

If ‘taters are on sale, grab extra and put them to good use here: Frittata with Potato, Potato Home Fries, and Greek Potato Wedges.

Overhead photo of a prepared potato leek gratin in a large casserole dish - before baking.

Chef expert tips for perfect results every time

  • Use a Mandoline Slicer or Food Processor. To ensure uniform cooking, be sure to use a mandoline or the slicing blade on your food processor for thin, even potato slices.
  • Clean Leeks Well. There’s a lot of grit and dirt hidden between the layers. Cut the leek in half lengthwise and then rise under cool running water thoroughly.
  • Layer Thoughtfully. Be sure to stir the potatoes in the cream sauce well and then use your hands to layer the potato slices in the casserole dish. You want to ensure each potato is coated with the cream mixture and the potatoes are evenly layered in the dish.
  • Bake Covered, Then Uncover. Cover the potato gratin during the first 40 minutes so the potatoes have a chance to steam and cook until tender. Then you’ll uncover the casserole and continue to bake until pale golden.
  • Add Cheese and Brown. To make sure the cheese on top doesn’t burn, you’ll add it to the top of the gratin during the last 25 minutes of cooking. This step ensures a crispy, golden crust.
  • Rest Before Serving. The potato leek gratin needs a chance to set up, so be sure to let it rest for at least 5 minutes, preferably 10.
  • Garnish It. Remember, you eat with your eyes first. A flurry of fresh herbs, shredded cheese, flakey salt, and freshly cracked pepper really brings this fleming’s potatoes recipe to life.
Close-up, overhead photo of Fleming potatoes garnished with grated parmesan cheese and chopped parsley.

FAQ: frequently asked questions

Below you’ll find the most common questions and answers about making this recipe. If you have a question you’d like answered, please drop it in the comments section below!

What kind of potatoes work best in gratin recipes? 

When making the best au gratin potatoes, the type of potato can make or break your dish.

For this Flemings potatoes recipe, you’ll want to use dry, floury potatoes (known as “baking potatoes), such as Russet potatoes. These potatoes are a great choice because they bake up tender, hold their shape, and soak up cream sauce like a dream. 

However, you can also use an in-between potato, such as Yukon gold potatoes, to make this potato gratin. However, since these potatoes are a little waxier, the gratin will end up a “creamier” or “soupy”.  

Take away: If you prefer a super saucy potato casserole, use Yukon golds. And, if you prefer a more classic dish, use Russets.

What’s the difference between scalloped potatoes and au gratin potatoes?

These two potato dishes are similar, so it often causes confusion. However, there are differences between potatoes grain and scalloped potatoes—mainly in the ingredients and technique.

  • Gratin Potatoes: Cheese is a defining feature of au gratin potatoes. And, this dish is typically made with a cream sauce that doesn’t include a flour thickener.  
  • Scalloped Potatoes: Traditional scalloped potatoes are made without cheese and instead made with a roux-thickened (or flour-thickened) béchamel sauce.

Which cheese is best for potato gratin?

Theres a wide variety of cheeses you can use when making a gratin-style potato dish. However, the most common or best cheeses are those that:

  • Melt smoothly
  • Medium flavor (not too underwhelming or overpowering)
  • Complement the cream sauce

The most popular cheese for potato casseroles choices include: Gruyère (nutty, slightly sweet), Cheddar (sharp or extra-sharp), Swiss (milder in flavor), and Parmesan or Pecorino Romano (harder cheese for garnishing or embellishing). But, it’s important to note, you’ll want to use a blend of two cheeses for complexity. 

Fleming’s steakhouse potatoes use a blend of cheddar (sharp) and Monterey jack (mild and buttery). However, I like to swap the Monterey jack out for pepper jack, which is the same creamy cheese, just with the addition of spicy chili peppers.

Do I have to use jalapeños?

No, you can absolutely skip the jalapeño peppers if you’d like. However, I personally think they add delightful subtle spice to leek potato gratin. If you don’t like them, you can leave them out entirely or replace them with mild chopped green chiles for a little less heat.

Can I make this fleming potatoes recipe ahead of time?

Absolutely. Just assemble the leek potato gratin up to 1 day ahead, cover tightly, and store in the refrigerator. When ready, remove the fleming potatoes recipe from the fridge and let it sit at room temperature for 30 minutes before baking. 

Serving potato gratin with leeks

This cheesy fleming potatoes recipe for gratin with leeks is endlessly versatile. Below are just a few ideas for a satisfying and mouthwatering dinner:

Unique serving suggestions

Close-up photo of a potato gratin made with leeks and jalapenos.

Storing leftovers

  • Refrigerator Storage: Allow leftover leek potato gratin to cool to room temperature before storing leftovers in an airtight container in the fridge for up to 4 to 5 days.
  • Reheating Instructions: For the best results, reheat the flemings potatoes in a 350-degree oven, covered, until warm and heated through. For a crispy top, remove the foil during the last part of reheating.
  • Freezing Instructions: Unfortunately, I don’t recommend freezing this recipe for potato au gratin due to the amount of cream and cheese.
Close-up photo showcasing the thin potato layers in a leek and potato gratin.

Bring deliciously indulgent steakhouse flavor straight to your kitchen with this Fleming’s potatoes recipe. Creamy, cheesy, beautifully golden, and perfectly comforting, it’s the kind of potato side dish that will leave everyone around your table asking for seconds (and thirds). Whether it’s a holiday gathering or simply a cozy Saturday night at home, this potato and leek gratin guarantees to steal the spotlight!

I hope you give it a try, and don’t forget to come back and leave a review! I love cheering you on in the kitchen.

Until next time, friends, cheers!

Cheyanne

Craving MORE? For more tasty recipe inspiration, be sure to follow me on Instagram, Pinterest, and Facebook. You can also get all of my newest content delivered straight to your inbox by signing up for my email newsletter.

More holiday potato side dishes! 

If you love these homemade au gratin potatoes, try one of these potato recipes next!

Overhead action photo of a serving spoon scooping flemings potatoes from a casserole dish.

Potatoes Au Gratin

5 from 6 votes
Author: Cheyanne Holzworth
Total Time: 1 hour 40 minutes
Prep Time: 20 minutes
Cook Time: 1 hour 20 minutes
Servings: 6 servings
Print Recipe Pin Recipe
Perfectly rich, beautifully cheesy, and deliciously legendary, these Fleming's potatoes are destined to steal the spotlight. With layers of velvety potatoes, buttery leeks, and a whisper of subtly spicy jalapeños—all in a silky cheese sauce, each bite is pure luxury. Ideally creamy and completely crave-able, one bite of this potato and leek gratin and you'll forget all about the entree!

Equipment

  • 1 Large Mixing Bowl
  • 1 Mandoline Slicer
  • 1 2 1/2 Quart Casserole Baking Dish

Ingredients 

  • 2 ½ TBS Unsalted Butter – DIVIDED
  • 2 medium Jalapeno Peppers – stemmed, seeded, and finely diced (about 1/3 cup)
  • 1 large Leek – white and light green parts only, thinly sliced (about 1 1/2 cups)
  • 2-3 cloves Garlic – peeled and minced
  • 3 ounces Colby Cheese – freshly shredded (about 1 cup)
  • 2.5 ounces Pepper Jack Cheese – freshly shredded (about 3/4 cup)
  • 3 Cups Heavy Cream – (24 ounces)
  • 1 ½ tsp Fresh Thyme Leaves – roughly chopped
  • 2.25 to 2.5 pounds Russet Potatoes – washed, dried, and peeled (about 3 medium potatoes) (SEE NOTES)
  • To taste Kosher Salt and Ground Black pepper
  • Optional Garnishes: Flakey Salt Freshly Cracked Black Pepper, Fresh Thyme, Fresh Parsley, Freshly Grated Parmesan Cheese

Instructions

  • Sauté Veggies and Aromatics: Heat 1 ½ tablespoons of butter in a skillet over medium to medium-high heat.
    Once melted, add the jalapeños, leeks, and season with ¼ teaspoon salt and a 1/8 tsp pepper. Sauté, stirring frequently, until the veggies are just softened, about 3 minutes.
    Then add the garlic and cook, stirring, until fragrant, about 30 seconds to 1 minute.
    Remove the skillet from the heat and transfer the veggie mixture to a plate. Set aside and let the veggies cool completely.
  • Preheat Oven and Prep Casserole Dish: Adjust oven rack to the center position and then preheat the oven to 400-degrees Fahrenheit.
    Use 1 tablespoon of butter to grease the inside of a 2 ½ quart casserole dish and then set the dish aside.
  • Mix Cheeses: To a large mixing bowl, add both shredded cheeses and mix them together.
    Then remove 1/3 of the shredded cheese (about ¾ cup), add it to a small bowl, and set it aside (this will be for topping the casserole).
  • Mix Cream Sauce: To the large bowl with the shredded cheeses, add the heavy cream, thyme leaves, and cooled leek-jalapeno mixture (from step 1). Season with 1 ¾ teaspoons kosher salt and ½ teaspoon pepper.
    Stir well to combine and then set aside.
  • Peel and Slice Potatoes: Use a mandoline or the slicing attachment on your food processor to carefully slice each peeled potato into 1/16- to 1/8-inch-thick coins.
  • Add Thinly Sliced Potatoes to Cream Mixture: Add the thinly sliced potatoes to the bowl with the cheese and cream mixture. Use your hands to gently toss the potatoes until every single slice is well coated.
    (Note: Try to make sure none of the potato slices are sticking together.)
  • Arrange Potatoes in Casserole Dish: Pour a quarter of the potato mixture into the prepared casserole dish and use your hands to spread them out evenly in the dish, making sure every slice of potato is well coated in the cream mixture.
    Continue dumping out and arranging all the sliced potatoes in the prepared baking dish.
    Then use a rubber spatula to scrape any excess cream and leek mixture from the bowl and pour it over the potatoes.
  • Bake Covered: Cover the dish tightly with aluminum foil and transfer to the preheated oven. Bake for 40 minutes.
    Remove from the oven and place the dish on a wire rack.
  • Uncover, Continue to Bake: Remove the foil and discard. Then return the potatoes to the oven and bake uncovered for 20-25 minutes, or until the top is a pale golden color.
    Remove from oven and place the dish on a wire rack.
  • Add Cheese, Continue to Bake: Sprinkle the reserved shredded cheese from step 3 evenly over the top of the potatoes.
    Then return the potato gratin to the oven and bake uncovered until the top is deeply golden in color and slightly crisped, about 22-28 additional minutes.
  • Rest, Garnish and Serve Potato Leek Gratin: Remove the potato au gratin from the oven and place on a wire rack. Let the casserole cool for at least 5 to 10 minutes.
    Sprinkle fresh thyme leaves, parsley, and parmesan cheese over the potato gratin and enjoy while warm.

Notes

  • Potatoes: I prefer russets as they absorb the creamy sauce better. But Yukon golds work too, just note the potato gratin will be “saucier” or “soupier”.
  • Need to Scale the Recipe? Hover your mouse over the number of servings in the recipe card. You’ll see a sliding scale pop up, you can use that to scale the recipe up or down as needed.
  • Got questions? I’ve got answers! If you ever run into an issue, have a question, or need any clarification – please feel free to drop them in the comments section. I’m happy to help when I can! 
  • Recipe serves: 6 to 8 as a side dish
Nutritional information is provided as a courtesy and the nutrition facts are an estimate based upon 6 servings. Exact information will depend upon the brands of ingredients and precise measurements used.

Nutrition

Calories: 693kcal    Carbohydrates: 37g    Protein: 14g    Fat: 56g    Saturated Fat: 36g    Polyunsaturated Fat: 2g    Monounsaturated Fat: 14g    Trans Fat: 0.2g    Cholesterol: 171mg    Sodium: 201mg    Potassium: 893mg    Fiber: 3g    Sugar: 5g    Vitamin A: 2422IU    Vitamin C: 17mg    Calcium: 300mg    Iron: 2mg
Course: Side Dish
Cuisine: French

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easy layered potatoes with cheese