Name: Keto Garlic Mushroom Chicken Casserole Recipe
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Ingredients: 2 pounds boneless skinless chicken thighs, cut into bite-size pieces; 2 tablespoons avocado oil or olive oil; 12 ounces cremini or baby bella mushrooms, sliced; 1 small yellow onion, finely diced; 4-5 cloves garlic, minced; 1 teaspoon fine sea salt, plus more to taste; 1 teaspoon black pepper; 4 ounces full-fat cream cheese, softened; 1 cup heavy whipping cream; 1 teaspoon Dijon mustard; 1 teaspoon Italian seasoning; 1 teaspoon smoked paprika or sweet paprika; 1 teaspoon onion powder; 1 teaspoon garlic powder; 1 tablespoon fresh lemon juice; 1 tablespoon fresh parsley, chopped, plus more for garnish; 1 1/2 cups shredded mozzarella cheese; 1/2 cup grated Parmesan cheese; 2 cups fresh spinach, roughly chopped; 1/2 cup cooked and crumbled bacon; 1/4 teaspoon red pepper flakes

Keto Garlic Mushroom Chicken Casserole Recipe tastes rich, creamy, and garlicky with juicy chicken and tender mushrooms tucked into a cheesy, low carb hug. It works perfectly for busy weeknights or casual entertaining, and you can get it on the table in about 45 minutes. I tested this version on my own family of picky Midwestern eaters, and they scraped the pan clean without asking where the pasta went.

Why Keto Garlic Mushroom Chicken Casserole Recipe Is Worth It

This casserole hits that cozy, comfort food spot while staying keto friendly and gluten free. You get savory garlic, earthy mushrooms, and juicy chicken in a creamy sauce that feels like restaurant food but uses simple ingredients.

You also prep everything in one skillet and one baking dish, so cleanup stays easy. Leftovers reheat beautifully, which means future you will thank present you when lunch tastes like a fresh home cooked meal.

“This Keto Garlic Mushroom Chicken Casserole Recipe tastes like a fancy steakhouse side dish met a weeknight chicken bake and decided to move into my meal rotation permanently. ★★★★★”

Ingredients You Need

Chicken and veggies

2 pounds boneless skinless chicken thighs, cut into bite size pieces
- Use thighs for juicier results; chicken breast works too, just watch the cook time.
2 tablespoons avocado oil or olive oil
12 ounces cremini or baby bella mushrooms, sliced
- White button mushrooms work in a pinch, but cremini bring deeper flavor.
1 small yellow onion, finely diced
4 to 5 cloves garlic, minced
1 teaspoon fine sea salt, plus more to taste
1 teaspoon black pepper

Creamy keto sauce

4 ounces full fat cream cheese, softened
- I like Philadelphia or store brand with no added starches.
1 cup heavy whipping cream
1 teaspoon Dijon mustard
1 teaspoon Italian seasoning or dried oregano and basil mix
1 teaspoon smoked paprika or sweet paprika
1 teaspoon onion powder
1 teaspoon garlic powder
1 tablespoon fresh lemon juice
1 tablespoon fresh parsley, chopped, plus more for garnish

Cheese topping

1 ½ cups shredded mozzarella cheese
½ cup grated Parmesan cheese
- Use real Parmesan, not the shelf stable shaker, for better melt and flavor.

Optional low carb add ins

2 cups fresh spinach, roughly chopped
½ cup cooked and crumbled bacon
¼ teaspoon red pepper flakes for a little heat

Pantry shortcuts and notes

Use pre sliced mushrooms and pre shredded cheese to save time, just choose low moisture brands without starch.
Jarred minced garlic works when you feel tired, though fresh garlic gives the best flavor.
If you track carbs very closely, scan labels on cream cheese and shredded cheese to avoid hidden starches.

Equipment list

Large oven safe skillet or sauté pan
- If your skillet cannot go in the oven, use a regular pan and transfer to a 9 by 13 inch baking dish.
Cutting board and sharp knife
Wooden spoon or spatula
Measuring cups and spoons
Mixing bowl for the sauce
9 by 13 inch casserole dish if needed
Aluminum foil

Quick Tips & substitutions

Brown the chicken in batches so it sears instead of steams.
Pat chicken dry with paper towels to help it brown and keep the sauce from watering down.
Use chicken breast instead of thighs and reduce the oven time by about 5 minutes so it stays juicy.
Swap heavy cream with full fat coconut cream for a dairy light version and keep the cream cheese if you tolerate it.
Stir in spinach or chopped kale at the end of the stovetop step for extra veggies without extra carbs.
Use rotisserie chicken as a shortcut; just shred 3 cups and skip the browning step.
Season as you go; taste the sauce before baking and adjust salt, pepper, and lemon juice.
Cover loosely with foil if the cheese browns too quickly while the center still needs time.

How to Make Keto Garlic Mushroom Chicken Casserole Recipe

Step 1: Prep and preheat

Preheat your oven to 375°F. Grease a 9 by 13 inch casserole dish if you plan to transfer from a skillet. Cut the chicken into bite size pieces and pat them dry with paper towels.

Season the chicken with salt and pepper on all sides. Slice the mushrooms, dice the onion, and mince the garlic so everything stands ready before you start cooking.

Step 2: Brown the chicken

Heat the avocado oil in a large skillet over medium high heat. Add half the chicken in a single layer and sear it for 3 to 4 minutes per side until it turns golden and cooked through in the center.

Transfer the browned chicken to a plate and repeat with the remaining chicken. Keep the browned bits in the pan since they add flavor to the sauce.

Step 3: Sauté mushrooms, onion, and garlic

Lower the heat to medium. Add the diced onion to the same skillet and cook for 2 to 3 minutes until it softens and turns translucent.

Add the sliced mushrooms and a pinch of salt. Cook for 5 to 7 minutes while you stir occasionally, until the mushrooms release their liquid and most of it cooks off.

Stir in the minced garlic and cook for 30 to 60 seconds until it smells fragrant. Do not walk away, since garlic burns quickly and turns bitter.

Step 4: Mix the creamy keto sauce

In a mixing bowl, add the softened cream cheese, heavy cream, Dijon mustard, Italian seasoning, smoked paprika, onion powder, garlic powder, lemon juice, and chopped parsley. Whisk until the mixture turns smooth and creamy with no big cream cheese lumps.

Taste the sauce and adjust with more salt, pepper, or lemon juice as needed. The sauce should taste slightly salty and bold since it will coat the chicken and veggies.

Step 5: Combine chicken, veggies, and sauce

Add the browned chicken and any juices back into the skillet with the mushrooms and onion. Pour the creamy sauce over the top.

Stir everything together until the chicken and mushrooms sit coated in the sauce. If you use spinach or kale, stir it in now and let it wilt for 1 to 2 minutes.

If your skillet can go in the oven, keep everything in the pan. If not, transfer the mixture to the greased casserole dish and spread it into an even layer.

Step 6: Add the cheese topping

Sprinkle the shredded mozzarella evenly over the top of the casserole. Follow with the grated Parmesan so it covers the surface.

If you use crumbled bacon or red pepper flakes, scatter them over the cheese. This topping gives the casserole that bubbly, golden, cheesy crust everyone fights over.

Step 7: Bake until bubbly

Place the skillet or casserole dish in the preheated oven. Bake for 18 to 22 minutes until the cheese melts, the edges bubble, and the top turns lightly golden.

If the top browns faster than you like, tent the dish loosely with foil. Check that the center feels hot and the sauce bubbles around the edges before you pull it out.

Step 8: Rest and garnish

Remove the casserole from the oven and let it rest for 5 to 10 minutes. This short rest helps the sauce thicken slightly so it scoops neatly.

Sprinkle with extra chopped parsley for color and freshness. Serve warm and watch everyone pretend they did not just come back for seconds.

Recipe Variations

Extra low carb: Skip the onion and use extra mushrooms and garlic to keep carbs even lower.
Gluten free: The recipe already stays gluten free as written; just confirm your cream cheese and shredded cheese contain no starch.
Dairy light: Use coconut cream instead of heavy cream and a dairy free cream cheese style spread, then top with a dairy free shredded cheese that melts well.
Vegan twist: Swap chicken with cubed extra firm tofu or tempeh, use coconut cream and vegan cream cheese, and add more mushrooms and spinach for heartiness.
Spicy version: Add red pepper flakes, a pinch of cayenne, or a chopped jalapeño with the onions.
Bacon lover: Stir cooked bacon into the sauce and sprinkle extra on top before baking.
Herb focused: Replace Italian seasoning with fresh thyme and rosemary for a more rustic flavor.

Ways to Serve Keto Garlic Mushroom Chicken Casserole Recipe

Spoon over cauliflower rice or mashed cauliflower for a cozy, low carb bowl.
Serve with a simple green salad with olive oil and lemon for a lighter plate.
Pair with roasted broccoli, green beans, or asparagus for extra veggies.
Stuff into lettuce wraps for a handheld option that still stays keto.
Serve with zucchini noodles or shirataki noodles when you miss pasta.

Storage Success

Let the Keto Garlic Mushroom Chicken Casserole Recipe cool to room temperature, then store leftovers in an airtight container in the fridge for up to 4 days. Reheat single portions in the microwave in 45 second bursts, or warm a larger amount in a covered dish in a 325°F oven until hot. If the sauce thickens too much after chilling, stir in a splash of cream or chicken broth while you reheat. You can also freeze portions for up to 2 months and thaw them overnight in the fridge before reheating.