This Pesto Spaghetti Squash Casserole is an easy, healthier version of lasagna! Spaghetti squash is layered with pesto ricotta, mozzarella and marinara. This spaghetti bake is budget-friendly, simple to prepare and a meal the entire family will love!Recipe can be scaled up or down by using the slider if you hover your mouse over the number of Servings.
1large Spaghetti Squash (about 4 to 4 ½ pounds)– halved lengthwise and seeds removed (SEE NOTES)
1-2TBSExtra Virgin Olive Oil- to taste
Kosher Salt & Ground Black Pepper
3CupsThick Marinara Sauce(SEE NOTES)
¼CupFresh Basil Leaves – thinly sliced, plus more for garnish
2CupsWhole Milk Ricotta Cheese
½heaping Cup Basil Pesto – Homemade or Store bought
1cloveGarlic – finely chopped
2/3CupFreshly Grated Parmesan Cheese - DIVIDED
8ouncesFresh Mozzarella – torn or shredded
Roast the spaghetti squash: Heat oven to 400 degrees F. Line a rimmed baking sheet with parchment paper for easy clean up. Rub the cut sides of the squash with olive oil and season to taste with salt and pepper. Place the squash, cut side down, on the prepared baking sheet. Transfer to the oven and bake for 40-50 minutes, or until the squash is tender and easily pierced with a fork. When squash is cooked and cool enough to handle, use a fork to gently scrape out the strands of squash and discard squash “shells”. Transfer the squash strands, in batches, to a kitchen towel or tea towel. Squeeze the excess water out of the spaghetti squash. Transfer to a bowl and set aside. Keep the oven at 400 degrees F.
While the spaghetti squash roasts, make the pesto ricotta mixture: In a medium bowl, combine the ricotta with the pesto, garlic, and 1/3 cup parmesan cheese. Season with ¼ teaspoon salt and 1/8 teaspoon ground black pepper. Stir to combine. Set aside.
Add flavor to your marinara: Stir fresh basil into your marinara sauce. Taste. Adjust your sauce to taste with salt and pepper. Set aside.
Assemble the casserole: Grease 9x13-inch casserole dish. Spread ¾ cup of the tomato sauce onto the bottom of the dish. Top with half of the cooked spaghetti squash noodles. Top with half (1 ½ cups) of the ricotta mixture followed by half (1 ¼ cups) of the remaining tomato sauce and half (4 ounces) of the mozzarella cheese. Repeat with the remaining squash noodles, ricotta and tomato sauce. Sprinkle with remaining mozzarella cheese and remaining 1/3 cup parmesan cheese.
Bake: Bake in the oven (preheated to 400 degrees F) for 25-30 minutes or until the top of the casserole is browned and bubbly.
Serve: Let cool 10 minutes before serving. Garnish with more parmesan cheese and fresh basil if desired. Enjoy!
You can use one large spaghetti squash or two smaller ones. Just make sure overall your squash measures roughly 4 to 4 ½ pounds. If you meal prep and have cooked spaghetti squash on hand, the equivalent is about 9 cups of cooked spaghetti squash strands.
To make the squash easier to cut in half: Use the tins of a fork to poke the outside of the squash a few times. Place the squash on a microwave safe plate and microwave on high for 3-5 minutes to soften the exterior before cutting.
If you like things spicy, add a teaspoon of crushed red pepper flakes to your marinara sauce!
For a different variation, try using Vodka Sauce instead! My easy homemade vodka sauce is delicious in this casserole! For recipe, click HERE.
Need protein? Feel free to add cooked, shredded chicken, turkey, ground beef or ground pork to the casserole! Or, if you prefer meat, try making this with homemade Bolognese instead of the tomato sauce!
Gluten-free? Make sure your marinara sauce is gluten-free!
To make your own spaghetti sauce: (Yield 3 Cups)2 TBS Olive Oil1 small Yellow Onion – finely diced3 cloves Garlic – chopped1 tsp EACH: Smoked Paprika & Dried Oregano1 TBS Tomato Paste1 (28 ounce) Can Peeled, Whole San Marzano Tomatoes – crushed by hand
Heat oil in a medium saucepot over medium heat. When the oil shimmers, add the onions and season with salt and pepper. Cook, stirring occasionally, for 5 minutes or until the onion are softened. Add in the garlic, paprika and oregano. Cook, stirring, until fragrant, about 30 seconds. Add in the tomato paste and cook, stirring, until the tomato paste starts to caramelize, about 1-2 minutes. Add in the tomatoes and season with salt and pepper.
Bring to a rapid simmer and then immediately reduce to a gentle simmer. Cook, stirring occasionally, for 40-45 minutes, or until sauce is thick. (Stir in basil from recipe above). Taste and adjust for seasoning. Remove from heat and set aside.
Recipe serves: 6-8Nutritional information is an approximation and based upon 8 servings.