Mushroom Polenta Casserole – Creamy Comfort Food with a Savory Twist

If you’re searching for a cozy, hearty, and flavor-packed dinner idea, this Mushroom Polenta Casserole is a perfect choice. Creamy polenta meets earthy sautéed mushrooms, fragrant garlic, and melted cheese, creating a vegetarian-friendly casserole that feels indulgent yet wholesome.

This dish works beautifully as a main course or as a side dish for holiday dinners. The combination of polenta’s smooth texture with the savory umami of mushrooms makes it irresistible for mushroom lovers.

Mushroom Polenta Casserole

Creamy polenta layered with sautéed mushrooms, garlic, herbs, and melted cheese 🍄🧀—a comforting vegetarian casserole perfect for dinner or holidays.

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Prep Time 25 minutes mins

Cook Time 30 minutes mins

Total Time 55 minutes mins

Servings: 6 portions

Course: Main Dish, Side Dish

Cuisine: American, Italian

Calories: 320

Ingredients Equipment Method Notes

Ingredients

  

• 1 cup polenta (coarse cornmeal)
• 4 cups milk or half milk, half broth
• 1 tbsp unsalted butter
• 1 cup shredded cheese Parmesan, Gruyère, or mozzarella
• salt and pepper
• 2 tbsp olive oil
• 1 tbsp butter
• 1 onion finely chopped
• 3 cloves garlic minced
• 1 lb mushrooms sliced
• 1 tsp fresh thyme or rosemary
• 0.5 cup shredded cheese for topping
• fresh herbs for garnish

Equipment

• Saucepan
• Large skillet
• Baking dish
• Wooden spoon
• Whisk

Method

 

1. In a saucepan, bring milk to a simmer. Gradually whisk in polenta and cook until creamy. Stir in butter, cheese, salt, and pepper.
2. Heat olive oil and butter in a skillet. Cook onion until soft, add garlic and mushrooms, sauté until golden. Season with thyme, salt, and pepper.
3. Grease a baking dish. Spread half of polenta, add mushrooms, then top with remaining polenta. Sprinkle cheese on top.
4. Bake at 375°F (190°C) for 25–30 minutes until golden and bubbly.
5. Rest 10 minutes before slicing. Garnish with herbs and serve warm.

Notes

Make-ahead friendly: Assemble and refrigerate overnight, then bake before serving. Easily adapted for vegan or gluten-free diets.

Why You’ll Love This Recipe

✅ Creamy, cheesy, and comforting
✅ Vegetarian-friendly and filling
✅ Perfect for make-ahead meals or holiday gatherings
✅ Rich umami flavor from mushrooms and garlic
✅ Crowd-pleasing side dish or main course

Ingredients

For the Polenta Base:

• 1 cup polenta (coarse cornmeal)
• 4 cups milk (or half milk, half broth for extra flavor)
• 1 tbsp unsalted butter
• 1 cup shredded cheese (Parmesan, Gruyère, or mozzarella)
• Salt & pepper, to taste

For the Mushroom Layer:

• 2 tbsp olive oil
• 1 tbsp butter
• 1 onion, finely chopped
• 3 garlic cloves, minced
• 1 lb mushrooms (button, cremini, or mixed), sliced
• 1 tsp fresh thyme or rosemary
• Salt & pepper, to taste

Topping:

• ½ cup shredded cheese
• Fresh herbs for garnish

Step-by-Step Instructions

1. Cook the Polenta
   • In a saucepan, bring milk (or milk + broth) to a simmer. Gradually whisk in polenta, stirring to prevent lumps. Cook on low heat, stirring, until thick and creamy (about 20 minutes). Stir in butter, cheese, salt, and pepper. Set aside.
2. Sauté the Mushrooms
   • Heat olive oil and butter in a skillet. Add onion and cook until softened. Stir in garlic and mushrooms, cooking until mushrooms are golden and liquid has evaporated. Season with salt, pepper, and thyme.
3. Assemble Casserole
   • Preheat oven to 375°F (190°C). Spread half the polenta into a greased baking dish. Layer mushrooms on top, then spread the remaining polenta over them. Sprinkle shredded cheese on top.
4. Bake
   • Bake uncovered for 25–30 minutes, until golden and bubbly.
5. Serve
   • Let casserole rest for 10 minutes before slicing. Garnish with fresh herbs and enjoy warm.

Tips & Variations

• Make it Vegan: Swap milk for almond or oat milk, butter for olive oil, and use vegan cheese.
• Add Protein: Stir in cooked lentils, beans, or shredded chicken for a heartier dish.
• Herb Upgrade: Add rosemary, sage, or parsley for extra flavor.
• Make Ahead: Prepare the casserole a day ahead and refrigerate. Bake before serving.

Why This Recipe Works

The casserole combines creamy, cheesy polenta with the earthy flavors of sautéed mushrooms, resulting in a balance of richness and umami. Baking enhances the flavors and creates a golden crust on top, making it ideal for both casual dinners and holiday meals.

Serving Ideas

• Serve as a main vegetarian dish with a green salad
• Pair as a side dish for roasted chicken, turkey, or beef
• Use leftovers for meal prep lunches—it reheats beautifully
• Slice into squares for a buffet or potluck dish