Mushroom Casserole - Healthy Recipes Blog (2024)

This deliciously cheesy mushroom casserole is wonderfully flavored with onions, thyme, and melted gruyere.

Made without breadcrumbs and ready in about 40 minutes, it's keto and gluten-free.

This casserole is amazing. It's so cheesy and flavorful! The wonderful aroma it releases when you cook it will let you know how good it's going to be.

Mushrooms are one of my favorite vegetables (well, technically they're fungi, not vegetables). And this tasty casserole is one of my favorite ways to cook them.

Ingredients

You'll only need a few simple ingredients to make this mushroom casserole. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:

Olive oil: A delicious oil and one of my favorites to cook with. It does have a relatively low smoke point, so you can use avocado oil instead.

Baby Bella mushrooms: You can also use white mushrooms if that's all you can find.

Salt and pepper: I use kosher salt in most of my recipes. If using fine salt, you will need to reduce the amount you use.

Aromatics: Onions and garlic. While jarred minced garlic is convenient, freshly minced tastes significantly better.

Spices: I use dried thyme and parsley.

Shredded Gruyere cheese: Gruyere tastes best, but I've made this casserole with shredded sharp cheddar and it was good too.

Instructions

Since mushrooms release quite a bit of liquid when cooked, you can't just put them in a dish and bake them. You need to saute them first.

So to make this recipe, I saute the mushrooms and chopped onions in olive oil until the mushrooms have released their liquid and most of the liquid has evaporated.

Check out the video below in the recipe card to see the process. See the steam? That's the mushroom's liquid, evaporating.

Once the liquid has mostly evaporated, you can transfer the mushrooms and onions to a greased baking dish, top them with cheese, and bake the casserole until the cheese has melted.

Expert tip

If your casserole dish is broiler-safe, you can simply broil the casserole for 2-3 minutes, in the middle of the oven, until the cheese is melted. You don't want to get too close to the heating element and risk burning the casserole.

Frequently asked questions

Variations

A good way to vary this recipe is by using different cheeses, such as cheddar, gouda, or provolone.

Another way is to experiment with different herbs and spices. Good options include smoked paprika, ground cumin, and dried oregano.

Serving suggestions

Mushrooms go well with steak, so I often make this recipe when I serve reverse-seared steak or London broil.

They are also excellent with chicken. Sometimes I slice baked chicken breast and top the slices with this casserole.

Since the mushrooms are not very colorful, it's nice to have a colorful veggie as a side, such as steamed broccoli or tomato salad.

Storing leftovers

Once the leftovers are cool, transfer them with a slotted spoon to an airtight container. Keep them in the fridge for up to 4 days. Reheat them in the microwave at 50% power.

Recipe Card

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