Name: Creamy Baked Mushroom and Cheese Casserole
Prep time: 15 min
Cook time: 35 min
Total time: 1 h
Yield: 8
Cuisine: American
Ingredients: 2 lbs (about 900g) fresh mushrooms (cremini or button), cleaned and sliced; 2 tablespoons butter; 1 medium onion, finely diced; 3 cloves garlic, minced; 1 teaspoon dried thyme (or 1 tablespoon fresh); Salt and black pepper, to taste; 2 tablespoons all-purpose flour; 1 ½ cups heavy cream; ½ cup sour cream; 1 cup shredded sharp cheddar cheese; 1 cup shredded Gruyère or mozzarella cheese; ½ cup grated Parmesan cheese; Fresh parsley, chopped (for garnish, optional)

This indulgent casserole features tender sautéed mushrooms swimming in a luscious creamy sauce infused with garlic and herbs, topped with a generous layer of melted cheeses that turn golden and bubbly in the oven. It’s earthy, velvety, and utterly satisfying — a crowd-pleasing baked mushroom masterpiece ready in under an hour.

Why You’ll Love This Recipe

You’ll adore this recipe because it’s incredibly easy yet feels gourmet — no fancy techniques required, just simple sautéing and baking for maximum flavor. The mushrooms release their natural juices, blending perfectly with the creamy base for that irresistible umami depth.

The cheeses melt into gooey perfection, creating a luxurious texture contrast with the tender veggies. It’s versatile for weeknight dinners, holiday sides, or potlucks, and even picky eaters rave about it. Low-effort, high-reward comfort food that warms the soul and leaves everyone asking for seconds!

Yield: 8 servings

Creamy Baked Mushroom and Cheese Casserole

Rich, cheesy baked mushrooms in creamy garlic sauce — ultimate comfort casserole!

Prep Time 15 minutes

Cook Time 35 minutes

Additional Time 10 minutes

Total Time 1 hour

Ingredients

2 lbs (about 900g) fresh mushrooms (cremini or button), cleaned and sliced
2 tablespoons butter
1 medium onion, finely diced
3 cloves garlic, minced
1 teaspoon dried thyme (or 1 tablespoon fresh)
Salt and black pepper, to taste
2 tablespoons all-purpose flour
1 ½ cups heavy cream
½ cup sour cream
1 cup shredded sharp cheddar cheese
1 cup shredded Gruyère or mozzarella cheese
½ cup grated Parmesan cheese
Fresh parsley, chopped (for garnish, optional)

Instructions

Get everything ready and preheat — Oh, the excitement begins! Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish with butter or oil. This ensures nothing sticks and cleanup is a breeze.
Sauté those gorgeous mushrooms — In a large skillet over medium-high heat, melt the butter. Add the sliced mushrooms in a single layer (do batches if needed), and cook for 5-7 minutes until they release their moisture and turn beautifully golden-brown. Stir occasionally for even browning — this step builds incredible flavor!
Add the aromatic magic — Toss in the diced onion and cook for another 3-4 minutes until softened and fragrant. Then stir in the minced garlic and thyme, cooking for just 1 minute more so the garlic doesn't burn — your kitchen will smell heavenly right now!
Season it up — Sprinkle salt and pepper generously over the mixture. Mushrooms love seasoning, so don't hold back — taste a bit and adjust.
Thicken the sauce base — Sprinkle the flour over the veggies and stir well for 1-2 minutes to cook out the raw flour taste. This creates that luscious, creamy texture we're craving.
Pour in the creamy dream — Slowly stir in the heavy cream, scraping up any browned bits from the pan bottom (flavor gold!). Bring to a gentle simmer and cook for 2-3 minutes until it thickens slightly. Remove from heat and fold in the sour cream for tangy richness.
Mix and taste — Give it a good stir, taste again, and tweak salt/pepper if needed. Transfer the creamy mushroom mixture to your prepared baking dish, spreading it evenly.
Cheese, glorious cheese! — Sprinkle the shredded cheddar and Gruyère (or mozzarella) evenly over the top, then finish with a generous layer of Parmesan for that golden, crispy edge.
Bake to bubbly perfection — Pop it into the oven and bake for 25-30 minutes, until the cheese is melted, golden, and irresistibly bubbly around the edges. Your patience will be rewarded!
Rest, garnish, and serve — Let it rest for 10 minutes to set up nicely. Sprinkle with fresh parsley if you like a pop of color and freshness. Scoop onto plates and watch everyone dive in with joy!

Notes

This dish is naturally vegetarian (use vegetable broth if adding any liquid). For best texture, avoid overcooking mushrooms initially — they continue baking. Pairs wonderfully with grilled meats, roasted chicken, or crusty bread to soak up the sauce.

Nutrition Information

Yield

Serving Size

1
Amount Per Serving Calories 405Total Fat 30gSaturated Fat 17gUnsaturated Fat 13gCholesterol 89mgSodium 716mgCarbohydrates 15gFiber 3gSugar 4gProtein 23g

The recipes and nutritional information on Yum Tonight are for informational purposes only. Always consult a healthcare provider for personalized dietary advice.

Recipe Tips and Tricks

Use a mix of mushroom varieties (cremini, button, shiitake) for deeper flavor layers.
Don’t overcrowd the pan when sautéing — cook in batches if needed so they brown instead of steam.
For extra creaminess, add a splash of white wine or sherry to deglaze the pan after cooking the mushrooms.
Grate your own cheese for better melting and avoid pre-shredded (which has anti-caking agents).
Let the casserole rest 5-10 minutes after baking to set the sauce and make serving easier.
Taste and adjust seasoning before baking — mushrooms soak up salt, so be generous!

Ingredients Notes

Fresh mushrooms are key here — opt for firm, plump ones like cremini (baby bella) or white button for mild earthiness; they hold up beautifully in baking without turning mushy. Heavy cream delivers that rich, velvety sauce, but half-and-half works for a lighter version.

Sour cream adds tangy brightness to balance the richness. Garlic and onion provide aromatic backbone, while thyme brings subtle herbal notes that pair magically with mushrooms.

A blend of cheeses (sharp cheddar for bite, Gruyère or mozzarella for meltiness, and Parmesan for nutty umami) creates the perfect gooey, golden topping. Butter for sautéing adds depth, and a touch of flour thickens the sauce into silky perfection.

Variations and Substitutions

Make it gluten-free by skipping any breadcrumbs or using GF flour for thickening. For a lighter take, swap heavy cream for half-and-half or evaporated milk, and use low-fat sour cream.

Add protein with cooked bacon bits, diced chicken, or ground sausage stirred in. Go vegetarian with spinach, broccoli, or peas for extra veggies. Switch cheeses — try Gouda for smokiness, fontina for ultra-creaminess, or blue cheese for bold tang.

For a crunchy topping, mix in panko breadcrumbs with the final cheese layer. Spice it up with a pinch of cayenne, smoked paprika, or truffle oil drizzle post-bake for gourmet flair.

Storage Options

Refrigerate leftovers in an airtight container for up to 3-4 days. Reheat in the oven at 350°F (covered with foil) for 15-20 minutes until warmed through, or microwave individual portions. Freeze unbaked (assemble, cover tightly) for up to 2 months — thaw overnight in the fridge and bake as directed, adding 10 extra minutes. Baked leftovers freeze well for 1 month; thaw and reheat gently to avoid separating the cream sauce.