Ingredients
Scale
- 1 pound mixed mushrooms (cremini, shiitake, and button), cleaned and sliced
- 3 tablespoons unsalted butter
- 1 medium yellow onion, finely chopped
- 3 cloves garlic, minced
- 1/4 cup all-purpose flour
- 2 cups whole milk (or substitute with unsweetened almond milk for a lighter version)
- 1/2 cup vegetable broth
- 1 teaspoon fresh thyme leaves, chopped (or 1/2 teaspoon dried thyme)
- 1 teaspoon fresh rosemary, finely chopped
- 1/2 cup grated Parmesan cheese (optional, for a richer casserole)
- 1 cup shredded Gruyère or mozzarella cheese
- Salt and freshly ground black pepper, to taste
- 1/2 cup panko breadcrumbs (for topping)
- 2 tablespoons olive oil
- Fresh parsley, chopped (for garnish)
Instructions
- Preheat your oven to 375°F. Lightly grease a 9×13-inch casserole dish and set aside.
- In a large skillet, melt the butter over medium heat. Add the chopped onion and sauté until translucent and soft, about 5 minutes. This step reminds me of my mother, Elena, improvising with whatever onions she could find, always coaxing out the sweetest flavors.
- Add the garlic and sauté for another minute until fragrant, being careful not to burn it.
- Toss in the sliced mushrooms and cook, stirring occasionally, until they release their moisture and begin to brown, about 8-10 minutes. This slow caramelization is key to building that deep, earthy flavor my Nonna prized.
- Sprinkle the flour over the mushroom mixture and stir well to coat everything evenly. Cook for 2 minutes to remove the raw flour taste.
- Gradually pour in the milk and vegetable broth while stirring constantly. The sauce will thicken as it heats—keep stirring to avoid lumps.
- Add the chopped thyme and rosemary, salt, and pepper to taste. Let the sauce simmer gently for about 5 minutes until creamy and luscious.
- Remove from heat and stir in the Parmesan and half of the shredded cheese until melted and well combined.
- Pour the creamy mushroom mixture into your prepared casserole dish, spreading it evenly.
- In a small bowl, toss the panko breadcrumbs with olive oil and sprinkle evenly over the casserole. Scatter the remaining shredded cheese on top to create a golden crust.
- Bake uncovered for 20-25 minutes, or until the topping is golden brown and bubbling around the edges.
- Remove from the oven and let rest for 5 minutes before serving. Garnish with fresh parsley for a pop of color and freshness.
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Main Dish
- Method: Cooking
- Cuisine: International
