Name: Baked Cheesy Mushrooms Casserole
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Ingredients: 1 lb button mushrooms (sliced); 1 tbsp olive oil (for seasoning); 1 tsp garlic powder (for seasoning); 1 tsp dried thyme (for seasoning); 1/2 tsp salt (to taste); 1/4 tsp black pepper (to taste); 1 cup shredded cheddar cheese (for topping); 1/2 cup grated Parmesan cheese (for topping); 1 cup heavy cream (for creamy sauce); 2 tbsp unsalted butter (melted, for breadcrumb topping); 1/2 cup breadcrumbs (optional, for crispy topping); 1 fresh parsley (chopped, for garnish)

This Baked Cheesy Mushrooms Casserole is one of those cozy, throw-it-together dishes that always hits the spot. It started on a night when I needed to use up some mushrooms, had a little cream, and just enough cheese left in the fridge. A quick sauté with garlic and herbs, a splash of cream, plenty of cheese on top—and into the oven it went. What came out was bubbling, golden, and absolutely delicious.

It’s simple enough for a weeknight but fancy-feeling enough to serve at a holiday table. You can use whatever mushrooms you’ve got, and play with the herbs and cheese depending on what’s on hand. I’ve made it as a side, as a vegetarian main with salad, and even taken it to potlucks. It’s warm, comforting, and always a crowd-pleaser.

Why You’ll Love This Recipe:

Creamy and Cheesy: The cheddar, Parmesan and heavy cream coalesce to create a cheesy, rich casserole that’s as satisfying as could be.

Quick Prep: The recipe is pretty quick to prepare and has just a few ingredients.

Versatile Side Dish: This goes with a lot of different types of main courses, and it’s an excellent choice for family meals or special events.

The Texture Orgy: The crunchy breadcrumb topping balances the creamy sauce with those soft shells in an all-texture ecstasy in your mouth.

Key Ingredients:

Button mushrooms: Button mushrooms provide a mild, tender taste, but cremini, or baby bella, mushrooms work here as well for a little bolder flavor.

Garlic Powder And Thyme: These spices have an earthy flavor that rounds out the richness of the mushrooms in a savory way that pairs really well with the creaminess.

As for Cheese: Cheddar melts nicely to gooey perfection + Parmesan: Parmesan is a great nutty topping, melted or grated.

Heavy Cream: Heavy cream, the sauce base, giving a rich, velvety texture to hold all ingredients together. For something a bit lighter, feel free to use half-and-half.

Breadcrumbs: Mixing breadcrumbs with melted butter lends a crusty finish; you can leave it out for a gluten-free dish or to lower the carbs.

Fresh Parsley: Provides a refreshing, herbaceous flavor and vibrant hue to the finished meal.

Full list of ingredients with amounts and instructions can be found in the recipe card below

Step-by-Step Instructions

Preheat the Oven:

Preheat oven to 375°F (190°C). Film a 9×13-inch baking dish with a little oil to keep it from sticking.

Season the Mushrooms:

Add the mushroom slices to a mixing bowl with olive oil, garlic, thyme, salt, and pepper. Toss until the mushrooms are well coated with the seasoning.

Layer the Dish:

Drain any excess oil from the mushroom mixture and spread evenly in the bottom of the prepared baking dish.

Add the Cheese:

Share the shredded cheddar and the grated Parmesan cheese evenly between the mushroom tops.

Pour the Cream:

Drizzle all of the heavy cream over the mushrooms and cheese in an even layer — it will become a creamy sauce as it bakes.

Make the Breadcrumb Topping:

In another bowl, stir together the melted butter and breadcrumbs until they’re fully combined. Chews needs a helping hand to get there (and to be honest, I think the crisp topping/chews are a match made in heaven), throughout the casserole.

Bake the Casserole:

Place the baking dish in the preheated oven; bake until golden brown on top and bubbling around the edges, 25 to 30 minutes.

Optional Broil:

For a crust with further crunch, broil the casserole for an additional 2 to three minutes after it comes out of the oven. Watch closely so they don’t burn.

Rest and Garnish:

Let the casserole rest for a few minutes to set. Give it a sprinkle of chopped parsley to finish.

Serving Suggestions:

Okay, so this casserole? It’s rich. Like, seriously cozy. Creamy, cheesy, a little earthy from the mushrooms—it’s the kind of thing that feels like a meal all on its own. But, if you wanna stretch it out or round it out, here’s what I usually throw on the plate:

Grilled chicken or steak – Something with a bit of char balances the creamy vibes. Honestly, even just a rotisserie chicken works if you’re in survival mode (been there).
Roast beef or pork – If you’re going full Sunday dinner, this casserole is the perfect sidekick. It doesn’t steal the spotlight, but it definitely makes the meal feel more like a hug.
Pasta or risotto – Yeah, carbs on carbs. No judgment. If you’ve got a veggie pasta or even a garlicky risotto, it weirdly works.
Roasted veg – When I’m pretending to eat healthy, I’ll throw some roasted Brussels sprouts or asparagus next to it. Adds a little bite, cuts the richness, makes me feel virtuous.

Point is, it’s flexible. You don’t need anything fancy—just something to hang out on the plate with it.

Storage and Reheating Tips:

This dish actually tastes better the next day. Like it had time to think about its life choices and decided to really show up.

In the fridge:

Spoon what’s left into a container with a lid (or, let’s be real, foil over a plate if it’s just for you). It’ll be fine for about 3 days. Just don’t forget it back there like last week’s mystery Tupperware.

In the freezer:

You can freeze it, if there’s any left. Let it cool all the way, then wrap it tight. Plastic wrap + foil is solid, or just use a freezer container if you’re fancy. Should be good for a month, maybe a little more.

To reheat:

Oven at 350°F for 10–15 minutes is your best bet if you’ve got time. If not? Microwave it. No shame. Add a splash of milk or cream if it’s looking a little thick or dry. Stir it around a bit and you’re good to go.

And hey—if you’re over it as a side dish, scoop it into a wrap, eat it on toast (no, seriously), or crack an egg on top and call it brunch. This casserole doesn’t judge.

A Few Ways to Change It Up

Spinach: If I’ve got spinach in the fridge, I’ll toss in a handful with the mushrooms. It cooks down fast and adds a little color and something green.
Low-Carb Option: You can skip the breadcrumbs altogether, or if you’re doing keto, crushed pork rinds work surprisingly well for a crispy top.
Cheese Swap: Don’t have cheddar? Use whatever you like—mozzarella melts nicely, and Gruyère makes it feel a little fancier.
Herbs: Sometimes I throw in a bit of rosemary, thyme, or basil—whatever’s growing or leftover. It adds a fresh, earthy flavor.
A Little Heat: Red pepper flakes in the topping are great if you like just a bit of spice. I don’t overdo it, but it wakes up the dish.

Conclusion:

I love this cheesy mushroom casserole—it’s one of those dishes that feels like a warm blanket on a plate. The mushrooms get all tender and savory, the cheese melts into every bite, and that little bit of crunch on top? So good.

It’s the kind of thing I make when I want something easy but still a little special. Whether it’s just a regular dinner or we’ve got family over, it always hits the mark. And honestly, leftovers—if there are any—might be even better the next day.