Keto Creamy Garlic Chicken and Mushroom Casserole

Some dinners just hit the spot after a long day, and this creamy chicken and mushroom casserole is one of them. It’s rich, comforting, and packed with simple ingredients that come together beautifully in the oven.

I love recipes like this because they don’t require a lot of prep or complicated ingredients. If you’ve got some cooked chicken ready to go, you’re already halfway there. The creamy sauce, tender mushrooms, and melted mozzarella do all the hard work when it comes to flavor.

This is the sort of meal that’s perfect for busy weeknights, but it’s also good enough to serve when you want something a little more special. Serve this with a simple side salad or your favorite low-carb vegetables, and dinner is sorted.

I have lots more Keto Casserole recipes so make sure you take a look at those too.

Ingredients

• Cooked chicken – Shredded rotisserie chicken works really well here and helps keep prep time to a minimum.

• Mushrooms – I usually use white mushrooms, but chestnut mushrooms add a little extra flavor if you have them on hand.

• Heavy cream – This gives the sauce its rich, creamy texture and helps bring everything together.

• Chicken broth – Adds extra flavor to the sauce while keeping it from becoming too heavy.

• Cream cheese – Make sure it’s softened first so it mixes smoothly into the sauce.

• Mozzarella cheese – Creates that irresistible melted cheese topping that makes this casserole so comforting.

• Garlic – Fresh garlic adds plenty of flavor and pairs perfectly with the chicken and mushrooms.

• Thyme – A little thyme adds a lovely savory flavor without overpowering the other ingredients.

• Salt and pepper – Season to taste and adjust as needed before baking.

• Olive oil – Used for cooking the mushrooms and garlic and helping them soften without sticking.

Recipe Instructions

Full measurements and cooking times can be found in the recipe card at the bottom of this post.

Step 1: Preheat your oven to 350°F (175°C).

Step 2: In a large skillet, heat olive oil over medium heat. Add the garlic and mushrooms, cooking until the mushrooms are tender and most of the liquid has been removed.

Step 3: In a bowl, mix together the cream cheese, heavy cream, chicken broth, thyme, salt, and pepper until smooth.

Step 4: Add the cooked chicken, mushroom mixture, and half of the mozzarella cheese to the bowl. Stir until everything is evenly combined.

Step 5: Pour the mixture into a greased 8×11-inch baking dish and top with the remaining shredded mozzarella cheese. Optional: top with extra mushroom slices.

Step 6: Bake for 25-30 minutes or until the casserole is bubbly and the cheese is melted. Allow to cool slightly before serving.

What to Serve with Low Carb Chicken and Mushroom Casserole

• Steamed broccoli – The creamy sauce pairs really well with broccoli, and it’s an easy way to add some extra vegetables to your plate.

• Cauliflower rice – If you’re keeping things low carb, cauliflower rice is perfect for soaking up all that creamy sauce.

• Roasted green beans – A side of roasted green beans adds a little texture and balances out the richness of the casserole.

• A simple side salad – Crisp lettuce, cucumber, and a light dressing make a great contrast to the warm, creamy casserole.

• Garlic butter zucchini – Zucchini cooks quickly and works beautifully alongside the chicken and mushroom flavors.

• Roasted Brussels sprouts – Their slightly crispy edges and savory flavor make them a great match for this comforting casserole.

Storing

Store any leftovers in an airtight container in the refrigerator for up to 3 days. When you’re ready to reheat, warm individual portions in the microwave or place the casserole in an oven-safe dish and heat until warmed through. The sauce may thicken slightly as it chills, but it will loosen up again as it reheats.

Variations & Substitutions

• Use rotisserie chicken – This is a great shortcut when you need dinner on the table quickly. Any cooked chicken works though.

• Try different mushrooms – White mushrooms, chestnut mushrooms, or a combination of both all work well in this casserole. I used Cremini mushrooms.

• Swap the mozzarella – Cheddar, Monterey Jack, or a blend of your favorite cheeses can be used instead of mozzarella.

• Add some extra vegetables – Stir in a handful of spinach, chopped broccoli, or zucchini for an easy way to add more veggies.

• Give it a little kick – A pinch of red pepper flakes or a dash of hot sauce can add a bit of heat without overpowering the creamy sauce.

• Use dried Italian seasoning – If you don’t have thyme on hand, Italian seasoning works well and adds plenty of flavor.

FAQs

Can I make this keto chicken and mushroom casserole ahead of time?

Yes. You can assemble the casserole up to a day in advance, cover it, and store it in the refrigerator until you're ready to bake. You may need to add a few extra minutes to the baking time if it's going into the oven straight from the fridge.

Can I use rotisserie chicken in chicken and mushroom casserole?

Absolutely. Rotisserie chicken is one of the easiest ways to make this recipe even quicker. Simply shred or dice the chicken and use it in place of any other cooked chicken.

Is this chicken and mushroom casserole low carb?

Yes. This casserole is naturally low in carbs thanks to the combination of chicken, mushrooms, cream cheese, heavy cream, and mozzarella cheese. It's a great option if you're looking for a filling low-carb dinner.

Can I freeze chicken and mushroom casserole?

You can, although cream-based sauces can sometimes change texture slightly after freezing and reheating. Allow the casserole to cool completely, then store it in a freezer-safe container for up to 3 months.

What mushrooms work best in chicken and mushroom casserole?

White mushrooms and chestnut mushrooms are both great choices for this recipe. You can also use a mixture of mushrooms if you'd like a little more variety and flavor.

How do I reheat leftover chicken and mushroom casserole?

Individual portions can be reheated in the microwave until hot throughout. For larger portions, cover the casserole dish with foil and warm it in the oven until heated through.

What can I serve with keto chicken and mushroom casserole?

This casserole pairs well with steamed broccoli, roasted green beans, cauliflower rice, zucchini, or a simple side salad. Any low-carb vegetable side works nicely with the creamy sauce.

Can I use a different cheese?

Yes. While mozzarella gives the casserole a mild, cheesy finish, you can swap it for cheddar, Monterey Jack, or your favorite cheese blend.