Portobello Stuffed Mushrooms

These baked Portobello Stuffed Mushrooms are my go-to when I want something that tastes restaurant-quality but still works for a weeknight dinner. Each meaty mushroom cap is loaded with a savory filling of spinach, garlic, Gruyère, Parmesan, and breadcrumbs, then baked until golden and bubbly.

📝 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

1. 1--- Pre-Cook Mushrooms ---
2. 2Preheat the oven to 375ºF. Line a baking sheet with parchment paper and set aside.
3. 3Wipe the mushrooms clean with a damp paper towel. Remove the stalks from the mushrooms, finely chop them and save for later. Scrape the gills from inside the mushrooms and discard.
4. 4Place the mushrooms on the baking sheet, open side up. Cook in the oven for 15 minutes after which time the mushrooms will have expelled some water/juice which can be reserved for later.
5. 5--- Make the Filling ---
6. 6Place a skillet or cast iron dish over a medium heat, and add the oil. When the oil is hot add the onion and sauté for about 2 minutes until soft, then add the garlic, chopped mushroom stalks and thyme, then cook for another minute.
7. 7Stir in the chopped spinach and juice from the cooked mushrooms. Cook for 1-2 minutes until the spinach has wilted then remove from the heat.
8. 8To the dish, add the breadcrumbs, Gruyère and Parmesan. Season with salt and pepper and mix until well combined.
9. 9--- Assemble & Bake ---
10. 10Divide the mixture between the mushrooms, pressing it down gently into the caps.
11. 11Bake for 15-20 minutes, or until the mushrooms are tender, the cheese is melted and the the tops are golden.
12. 12Scatter over the chopped parsley, a few extra thyme leaves and a little extra parmesan to serve.
13. 13Note: I provide helpful step-by-step photos below this recipe card. ⬇️⬇️