5 from 5 votes
Overhead landscape photo of Oven Roasted Mushrooms and Onions garnished with fresh herbs and lemon wedges in a white serving bowl with a pale tan napkin and ramekin of fresh oregano next to the bowl.
Oven Roasted Mushroom recipe
Prep Time
5 mins
Cook Time
20 mins
Total Time
25 mins
This Oven Roasted Mushroom recipe is super easy to make and only requires 5 minutes of hands on preparation!  Baked with a simple wine and garlic infused butter sauce, this steakhouse-style mushroom side dish is incredibly flavorful and extremely versatile!
Course: Appetizer, Side Dish
Cuisine: American
Keyword: mushrooms, onions, Oven Baked, Oven Roasted
Servings: 6 servings
Calories: 169 kcal
  • 1 pound Mushrooms (Cremini or White Button) – cleaned and stems trimmed to be flush with the caps
  • 8 ounces Frozen Pearl Onions – defrosted (SEE NOTES)
  • 2 TBS Olive Oil
  • Sea Salt & Ground Black Pepper
  • 5 TBS Unsalted Butter – cubed
  • 1/3 Cup Good Dry White Wine
  • 2-3 cloves Garlic - minced
  • 2 tsp EACH: Fresh Thyme & Fresh Oregano – chopped, plus more sprigs for roasting
Garnish: Fresh Parsley/Thyme, Lemon Wedges
  1. Preheat oven to 425 degrees F.

  2. Season mushrooms: Place mushrooms and onions on a large, rimmed baking dish. Toss with oil and season with a pinch of salt and pepper. Arrange the vegetables in a single layer, with the mushrooms facing stem side down. Add 4 sprigs of fresh thyme and 2 sprigs of rosemary to the baking dish.

  3. Partially roast: Place mushrooms and onions in the oven. Roast for 15 minutes or until lightly browned.

  4. While the mushrooms are roasting, make the butter sauce: (SEE NOTES) In a large, microwave-safe liquid measuring cup, combine butter, wine, garlic, thyme and oregano. Season with ¼ teaspoon salt and 1/8 teaspoon pepper. Microwave at 1 for 1 minute. Stir and microwave again for 1 ½ in 30 second increments.

  5. Toss with butter and finish roasting: Remove mushrooms and onions from the oven. Drizzle the butter sauce over the vegetables and gently toss or stir to coat. Continue roasting for 5-10 minutes or until mushrooms are browned and tender. Taste and adjust for seasoning with salt and pepper.

  6. Serve: Transfer mushrooms and onions to a serving dish. Drizzle with butter sauce from the baking dish. Garnish with fresh herbs and lemon if using. Enjoy!

Recipe Notes
  1. When selecting mushrooms, make sure you pick ones that are roughly the same size for even cooking!
  2. If you can’t find pearl onions or simple don’t like them, feel free to substitute 8 ounces of thickly sliced shallots instead! Alternatively, you can omit the onions completely and use an extra 8 ounces of mushrooms!
  3. When making the butter sauce in the microwave, be very careful! The wine and butter mixture will bubble up when it is heating, so make sure you are using a large measuring cup and microwave in short increments! I recommend at least a 2 cup liquid measuring cup.  Alternatively, you can melt the butter with wine, garlic and seasonings on the stove-top!

Nutritional information is an approximation and based upon 6 servings.

Nutrition Facts
Oven Roasted Mushroom recipe
Amount Per Serving
Calories 169 Calories from Fat 126
% Daily Value*
Fat 14g22%
Saturated Fat 7g44%
Cholesterol 25mg8%
Sodium 8mg0%
Potassium 305mg9%
Carbohydrates 7g2%
Fiber 1g4%
Sugar 3g3%
Protein 3g6%
Vitamin A 292IU6%
Vitamin C 5mg6%
Calcium 16mg2%
Iron 1mg6%
* Percent Daily Values are based on a 2000 calorie diet.