Introduction

Portobello stuffed mushrooms make a delicious and elegant appetizer or side dish that’s packed with savory flavors. Filled with a cheesy spinach mixture and fresh herbs, these mushrooms are easy to prepare and perfect for any occasion.

Portobello Stuffed Mushrooms with Spinach, Gruyère, and Parmesan Recipe - Recipe Image

Ingredients

4 large Portobello mushrooms
2 tablespoons olive oil
1/2 small onion, finely diced
2 cloves garlic, minced
2 sprigs fresh thyme, stalks removed
2 cups fresh spinach, chopped
1/2 cup breadcrumbs
1/2 cup Gruyère cheese, shredded
1/4 cup Parmesan cheese, grated
2 tablespoons fresh parsley, finely chopped
Salt and pepper, to taste

Instructions

Step 1: Preheat the oven to 375ºF and line a baking sheet with parchment paper.
Step 2: Wipe the mushrooms clean with a damp paper towel. Remove the stalks, finely chop them, and set aside. Scrape out and discard the gills from inside the mushrooms.
Step 3: Place the mushroom caps open side up on the baking sheet and bake for 15 minutes. Reserve any juices the mushrooms release for later use.
Step 4: Heat the olive oil in a skillet over medium heat. Add the onion and sauté until soft, about 2 minutes. Add the garlic, chopped mushroom stalks, and thyme, cooking for another minute.
Step 5: Stir in the chopped spinach and mushroom juices. Cook until the spinach wilts, about 1-2 minutes, then remove from heat.
Step 6: Add breadcrumbs, Gruyère, and Parmesan to the skillet. Season with salt and pepper and mix well to combine.
Step 7: Spoon the filling evenly into the mushroom caps, pressing it down gently.
Step 8: Bake the stuffed mushrooms for 15-20 minutes, until the mushrooms are tender, cheese has melted, and tops are golden brown.
Step 9: Garnish with chopped parsley, extra thyme leaves, and a sprinkle of Parmesan before serving.

Tips & Variations

For a richer flavor, try adding a splash of white wine to the spinach mixture while cooking.
Use gluten-free breadcrumbs to make the recipe suitable for gluten-sensitive diets.
Swap Gruyère with mozzarella or feta for a different cheese profile.
Serve as a main course by adding cooked quinoa or rice to the filling for more substance.

Storage

Store leftover stuffed mushrooms in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350ºF until warmed through to maintain texture and flavor. Avoid microwaving if possible, as it can make the mushrooms soggy.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare these mushrooms in advance?

Yes, you can assemble the stuffed mushrooms ahead of time and keep them covered in the refrigerator for a few hours before baking. Bake just before serving for best results.

Can I use other types of mushrooms?

While Portobello mushrooms work best because of their size and sturdy caps, you can use large cremini or button mushrooms for smaller portions. Adjust cooking time accordingly.

Portobello Stuffed Mushrooms with Spinach, Gruyère, and Parmesan Recipe

Print Recipe

★★★★★

4.8 from 76 reviews

Delicious and hearty Portobello Stuffed Mushrooms filled with a savory mixture of sautéed onions, garlic, spinach, breadcrumbs, and a blend of Gruyère and Parmesan cheeses, baked to golden perfection and topped with fresh herbs.

Author: Elias
Prep Time: 15 minutes
Cook Time: 35 minutes
Total Time: 50 minutes
Yield: 4 servings 1x
Category: Appetizer
Method: Baking
Cuisine: American
Diet: Vegetarian

Ingredients

Scale

Mushrooms

4 large Portobello mushrooms

Filling

2 tablespoons olive oil
1/2 small onion, finely diced
2 cloves garlic, minced
2 sprigs fresh thyme, stalks removed
2 cups fresh spinach, chopped
1/2 cup breadcrumbs
1/2 cup Gruyère cheese, shredded
1/4 cup Parmesan cheese, grated
2 tablespoons fresh parsley, finely chopped
Salt and pepper, to taste

Instructions

Preheat Oven: Preheat the oven to 375ºF (190ºC) and line a baking sheet with parchment paper to prepare for baking the mushrooms.
Prepare Mushrooms: Wipe the Portobello mushrooms clean with a damp paper towel. Remove the stalks, finely chop them and set aside. Scrape out and discard the gills from inside each mushroom cap.
Pre-cook Mushrooms: Place the mushroom caps on the baking sheet, open side up, and bake in the oven for 15 minutes to release moisture. Reserve any juice released during this process for the filling.
Make the Filling Base: Heat a skillet or cast iron pan over medium heat and add the olive oil. Sauté the diced onion for about 2 minutes until softened. Add the minced garlic, chopped mushroom stalks, and fresh thyme leaves, cooking for an additional minute to combine flavors.
Add Greens and Mushroom Juice: Stir in the chopped spinach and reserved mushroom juice. Cook for 1-2 minutes until the spinach is wilted, then remove the skillet from the heat.
Combine Filling Ingredients: To the cooked mixture, add breadcrumbs, shredded Gruyère, grated Parmesan, salt, and pepper. Mix thoroughly until the filling is well combined and cohesive.
Stuff Mushrooms: Divide the filling evenly among the mushroom caps, pressing it gently into each one to fill them completely.
Bake Stuffed Mushrooms: Return the mushrooms to the oven and bake for 15-20 minutes, or until the mushrooms are tender, the cheese has melted, and the tops are golden brown.
Garnish and Serve: Remove from the oven and sprinkle the stuffed mushrooms with finely chopped fresh parsley, a few extra thyme leaves, and extra Parmesan cheese to enhance flavor and presentation.

Notes

To make cleaning mushrooms easier, avoid rinsing under water; use a damp paper towel instead.
Reserve the mushroom juice expelled during pre-cooking to add extra moisture and flavor to the filling.
Use a cast iron skillet or heavy-bottomed pan to evenly sauté vegetables and enhance flavor development.
For a vegetarian version, ensure that the bread crumbs and cheeses used do not contain animal rennet.

Keywords: Portobello mushrooms, stuffed mushrooms, baked mushrooms, vegetarian appetizer, Gruyère cheese, Parmesan cheese, spinach, savory filling