After years of cooking for my family, I’ve discovered that the best recipes are those that bring comfort and nutrition together. That’s exactly what this mushroom keto casserole delivers! As someone who follows a low-carb lifestyle, I’m always looking for dishes that satisfy my cravings without the guilt. This casserole has become my go-to recipe when I want something rich, creamy, and utterly delicious. The combination of earthy mushrooms, savory cheese, and aromatic herbs creates a symphony of flavors that’ll have everyone asking for seconds. Trust me, this dish will become a staple in your kitchen too!

Why You’ll Love This Mushroom Keto Casserole

This mushroom keto casserole isn’t just another low-carb recipe—it’s a game-changer for busy weeknights. With only 10 minutes of prep time, you’ll have a gourmet-style dish that tastes like you spent hours in the kitchen. The beauty of this recipe lies in its simplicity and versatility. Whether you’re cooking for picky eaters or health-conscious friends, this casserole hits all the right notes. It’s naturally gluten-free, keto-friendly, and can easily be customized with your favorite add-ins like chicken or spinach.

Ingredients Overview

Prep Time: 10 minutes | Cook Time: 30 minutes | Total Time: 40 minutes
Servings: 6 | Difficulty: Easy

How to Make Mushroom Keto Casserole

Now comes the fun part—let’s get cooking! I’ve broken down this recipe into simple steps that even beginner cooks can follow with confidence. The key to a perfect mushroom keto casserole is building layers of flavor, and I’ll show you exactly how to do it.

Step 1: Preheat Your Oven

Start by preheating your oven to 350°F (175°C). This might seem basic, but trust me, a properly preheated oven ensures even cooking and that gorgeous golden-brown top we’re after. While the oven heats up, you can prep your ingredients.

Step 2: Sauté the Aromatics

Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3-4 minutes until it becomes translucent. The smell alone will make your mouth water! Next, add the minced garlic and cook for another minute. Pro tip: don’t let the garlic brown, as it can become bitter.

Step 3: Cook the Mushrooms

Add the sliced mushrooms to the skillet. Here’s where patience pays off—cook them for 6-8 minutes until they release their moisture and turn golden brown. Don’t rush this step! Properly cooked mushrooms develop a deep, umami flavor that’s the heart of this casserole. Season with salt, pepper, and dried thyme.

Step 4: Create the Creamy Base

Pour in the heavy cream and let it simmer for 2-3 minutes. The cream will pick up all those delicious flavors from the pan. If you’re adding chicken or spinach, fold them in now. The spinach will wilt beautifully, and the chicken will warm through.

Step 5: Add the Cheese

Remove the skillet from heat and stir in half of both cheeses. The residual heat will melt them perfectly, creating a luscious, creamy sauce that coats every mushroom.

Step 6: Assemble and Bake

Transfer the mixture to a greased 9×9-inch baking dish. Sprinkle the remaining cheese on top for that irresistible crusty layer. Bake for 25-30 minutes until bubbly and golden.

Serving and Variations

Let this mushroom keto casserole rest for 5 minutes before serving—it’ll be easier to portion and the flavors will settle beautifully. I love serving this with a crisp arugula salad dressed with lemon vinaigrette to cut through the richness. For a complete keto meal, pair it with roasted asparagus or steamed broccoli.

Creative Variations

Over the years, I’ve experimented with this recipe, and here are my favorite twists:

• Italian Style: Add sun-dried tomatoes and fresh basil, substitute mozzarella with fontina cheese
• Mexican Flair: Include chorizo, jalapeños, and top with pepper jack cheese
• Truffle Luxe: Drizzle truffle oil before serving for an elegant touch
• Veggie Loaded: Mix in roasted bell peppers, zucchini, or cauliflower rice

Storage Tips

This casserole keeps wonderfully! Store leftovers in an airtight container for up to 4 days in the fridge. For meal prep, portion it into individual containers. It reheats beautifully in the microwave or oven—just add a splash of cream if it seems dry.

Frequently Asked Questions

Can I make this mushroom keto casserole ahead of time? Absolutely! Assemble the casserole, cover tightly, and refrigerate for up to 24 hours before baking. Add 5-10 minutes to the cooking time if baking straight from the fridge.

What type of mushrooms work best?
I prefer cremini or baby bella mushrooms for their meaty texture, but white button mushrooms work great too. For a gourmet touch, mix in some shiitake or oyster mushrooms.

Can I freeze this casserole?
Yes! Cool completely, wrap well, and freeze for up to 3 months. Thaw overnight in the fridge before reheating. The texture might be slightly different, but it’ll still taste amazing.

How do I prevent a watery casserole?
The key is cooking the mushrooms until they’ve released and reabsorbed their moisture. Also, don’t skip the resting time after baking—it helps everything set properly.

Is this recipe dairy-free adaptable?
While this recipe relies heavily on dairy, you could experiment with cashew cream and nutritional yeast, though the flavor profile will be quite different.

Mushroom Keto Casserole

A rich, creamy, and low-carb mushroom casserole that's perfect for busy weeknights. Easy to make with simple ingredients, this keto-friendly dish delivers comfort and nutrition in every bite.

Print Recipe Pin Recipe

Prep Time 10 minutes mins

Cook Time 30 minutes mins

Total Time 40 minutes mins

Course Dinner

Cuisine American

Servings 6

Calories 300 kcal

Ingredients

  

• 1 lb fresh mushrooms any variety, sliced
• 1 medium onion diced
• 3 cloves garlic minced
• 1 cup heavy cream full-fat
• 1 cup shredded mozzarella cheese
• 1 cup grated Parmesan cheese
• 2 tbsp olive oil extra virgin preferred
• 1 tsp dried thyme or fresh thyme
• 1 tsp salt to taste
• ½ tsp freshly ground black pepper
• 1 cup cooked chicken optional, shredded
• 1 cup fresh spinach optional

Instructions

 

• Preheat the oven to 350°F (175°C).
• Heat olive oil in a large skillet over medium heat. Add diced onion and cook for 3-4 minutes until translucent. Add garlic and cook for another minute.
• Add sliced mushrooms and cook for 6-8 minutes, allowing them to release moisture and turn golden brown. Season with salt, pepper, and dried thyme.
• Pour in the heavy cream and simmer for 2-3 minutes. If adding chicken or spinach, fold them in now.
• Remove from heat and stir in half of both mozzarella and Parmesan cheeses.
• Transfer the mixture to a greased 9×9-inch baking dish and top with the remaining cheese.
• Bake for 25-30 minutes, until bubbly and golden.

Notes

Let the casserole rest for 5 minutes before serving.

Serve with a fresh salad or keto-friendly vegetables like roasted asparagus or steamed broccoli.

You can make this casserole ahead of time by assembling it and refrigerating for up to 24 hours before baking. Add 5-10 minutes to the cook time if baking from the fridge.

For variations, try adding sun-dried tomatoes, chorizo, jalapeños, or truffle oil for different flavor profiles.

This recipe can be frozen for up to 3 months—just be sure to thaw overnight in the fridge before reheating.

Keyword low-carb casserole, Mushroom Keto Casserole