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Slow-Cooked Mushroom Casserole

This mushroom casserole highlights earthy, umami-rich mushrooms cooked slowly to develop deep flavor and a velvety, fragrant sauce. Topped with crispy breadcrumbs and melted cheese, it offers a comforting, rustic dish with a rich, golden-brown appearance and tender texture. Perfect for chilly evenings, it combines simple ingredients into a decadent, satisfying meal.
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Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes
Servings: 4
Course: Main Course
Cuisine: European
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 500 g mushrooms (cremini or button) sliced about 0.5 cm thick
  • 2 tbsp butter unsalted
  • 1 small onion finely chopped
  • 3 cloves garlic minced
  • 1 cup heavy cream or substitute with coconut or cashew cream
  • 1/2 cup grated cheese Gruyère or sharp cheddar
  • a handful panko breadcrumbs toasted for crunch
  • fresh thyme or parsley chopped, for garnish
  • salt and pepper to taste

Equipment

  • Large Skillet
  • 9x13 inch baking dish
  • Spatula or wooden spoon
  • Grater
  • Measuring cups and spoons
  • Oven

Method
 

  1. Preheat your oven to 180°C (350°F). Prepare a 9x13 inch baking dish and set aside.
  2. Slice the mushrooms into even pieces and season lightly with salt and pepper. Heat a large skillet over medium heat and melt the butter until it’s bubbling and fragrant.
  3. Add the sliced mushrooms to the skillet. Sauté them for about 8-10 minutes, stirring occasionally, until they release their juices and turn a deep golden brown—this aroma of earthy caramelization will fill your kitchen.
  4. Push the mushrooms to one side of the skillet. In the same pan, add a little more butter if needed, then sauté the finely chopped onion and minced garlic until soft and fragrant, about 3-4 minutes. You’ll notice the mixture becoming translucent and aromatic.
  5. Pour in the heavy cream and sprinkle in the grated cheese. Stir gently until the sauce thickens slightly and becomes glossy, about 2-3 minutes. If it’s too thick, add a splash of milk; if too thin, simmer a bit longer until it’s velvety.
  6. Transfer the mushroom mixture into your prepared baking dish, spreading it evenly. Top with toasted panko breadcrumbs for a crispy finish and sprinkle with chopped herbs like thyme or parsley.
  7. Bake uncovered for about 25-30 minutes until the top is golden brown and crispy, and the sauce is bubbling around the edges. The aroma of cheesy, earthy goodness will make your mouth water.
  8. Remove the casserole from the oven and let it rest for 5 minutes. Garnish with additional chopped herbs if desired, then serve warm, enjoying the rich, velvety sauce with a crispy topping and tender mushrooms.

Notes

For a vegan version, substitute plant-based cream and cheese. To add extra flavor, incorporate sautéed mushrooms or herbs of your choice. Resting the casserole briefly helps the sauce set for cleaner servings.