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; 16 ounces cremini or baby bella mushrooms, sliced; 1 small yellow onion, finely diced; 4-6 cloves garlic, minced; 2 tablespoons fresh parsley, chopped, plus more for garnish; 1 teaspoon fresh thyme leaves or 1/2 teaspoon dried thyme; 2 tablespoons avocado oil or light olive oil; 3 tablespoons butter; 3/4 cup low sodium chicken broth; 1 cup heavy whipping cream; 1 1/2 cups shredded low moisture part skim mozzarella cheese; 1/2 cup grated Parmesan cheese; 2 ounces cream cheese, softened and cubed; 1/2 teaspoon xanthan gum; 1 1/4 teaspoons fine sea salt, plus more to taste; 3/4 teaspoon black pepper; 1/2 teaspoon smoked paprika; 1/2 teaspoon garlic powder; 1/4 teaspoon onion powder; 1 pinch red pepper flakes

Keto Garlic Mushroom Chicken Casserole Recipe tastes rich, creamy, and garlicky with juicy chicken and tender mushrooms in every bite. It works perfectly for busy weeknights or low carb meal prep, and you can get it on the table in about 45 minutes. I first made a version of this on a chaotic Tuesday when my kids staged a coup against zucchini, and this casserole saved dinner and my sanity.

Why You Should Try This Keto Garlic Mushroom Chicken Casserole Recipe

This casserole hits all the cozy comfort food notes while staying low carb and gluten free. You get juicy chicken, caramelized mushrooms, and a cheesy garlic cream sauce that feels like restaurant food but cooks in one pan.

It suits keto eaters, low carb families, and anyone who just loves a hearty chicken and mushroom bake. You can prep it ahead, bake it later, and it reheats like a dream on busy nights.

“This Keto Garlic Mushroom Chicken Casserole Recipe tastes like a fancy steakhouse side turned into a full dinner, and my whole family licked their plates clean. ★★★★★”

Ingredients You’ll Need

Chicken and veggies

2 pounds boneless skinless chicken thighs, cut into bite-size pieces
- Use thighs for juicier meat; use chicken breast if you prefer leaner meat and shorten the cook time slightly.
16 ounces cremini or baby bella mushrooms, sliced
- White button mushrooms work, but cremini give deeper flavor.
1 small yellow onion, finely diced
4 to 6 cloves garlic, minced
2 tablespoons fresh parsley, chopped, plus more for garnish
1 teaspoon fresh thyme leaves or ½ teaspoon dried thyme

Fats and liquids

2 tablespoons avocado oil or light olive oil
3 tablespoons butter (salted or unsalted, adjust salt if needed)
¾ cup chicken broth, low sodium
- I like Kettle & Fire or any clean brand without added sugar.
1 cup heavy whipping cream
- Use full fat coconut cream as a dairy free option, though flavor changes slightly.

Cheese and thickener

1 ½ cups shredded mozzarella cheese, low moisture, part skim
½ cup grated Parmesan cheese
2 ounces cream cheese, softened and cubed
- Choose full fat cream cheese for best keto macros.
½ teaspoon xanthan gum (optional, for thicker sauce)
- Skip this if you prefer a looser sauce or use 1 teaspoon coconut flour as an alternative thickener.

Seasonings

1 ¼ teaspoons fine sea salt, plus more to taste
¾ teaspoon black pepper
½ teaspoon smoked paprika
½ teaspoon garlic powder
¼ teaspoon onion powder
Pinch of red pepper flakes (optional, for a little heat)

Equipment

Large oven safe skillet or braiser, about 12 inches wide
- If you do not have one, use a regular skillet for the stovetop steps and transfer to a 9×13 baking dish.
Cutting board and sharp knife
Wooden spoon or spatula
Measuring cups and spoons
Cheese grater if you shred your own cheese
Aluminum foil (optional, to keep the top from over browning)

Tips & Tricks

Pat the chicken dry with paper towels so it browns nicely and does not steam.
Brown chicken in batches so you avoid crowding the pan and keep good color and flavor.
Slice mushrooms on the thicker side so they stay meaty and do not disappear into the sauce.
Let mushrooms cook until they release liquid and start to brown so they taste deep and savory.
Use room temperature cream cheese so it melts into the sauce without lumps.
Add xanthan gum by sprinkling it lightly over the bubbling sauce while you whisk so it does not clump.
Shred cheese from a block since pre shredded cheese often contains starch that can affect melting and carbs.
Taste the sauce before baking and adjust salt, pepper, and garlic so it matches your preference.
Broil the casserole for 1 to 2 minutes at the end if you want extra golden, bubbly cheese on top.
Let the casserole rest 5 to 10 minutes before serving so the sauce thickens and the portions scoop cleanly.

How to Make Keto Garlic Mushroom Chicken Casserole Recipe

Step 1: Prep the ingredients and preheat the oven

Preheat your oven to 375°F.
Cut the chicken into bite-size pieces and pat them dry.
Slice mushrooms, dice onion, mince garlic, and cube the cream cheese so everything stands ready to go.

Step 2: Brown the chicken

Heat 1 tablespoon oil and 1 tablespoon butter in your large oven safe skillet over medium high heat.
Season the chicken with salt, pepper, and smoked paprika.
Add half the chicken to the hot pan and cook 3 to 4 minutes per side until browned and cooked through, then transfer to a plate.
Repeat with the remaining oil, chicken, and another tablespoon of butter, then set all browned chicken aside.

Step 3: Cook the mushrooms and aromatics

Lower the heat to medium and add the remaining tablespoon of butter to the same skillet.
Add the onion and cook 2 to 3 minutes until it softens and turns translucent.
Stir in the mushrooms, season with a pinch of salt, and cook 6 to 8 minutes until they release their liquid and start to brown.
Add the minced garlic, thyme, garlic powder, onion powder, and red pepper flakes, then cook 1 minute until fragrant.

Step 4: Build the creamy garlic mushroom sauce

Pour in the chicken broth and scrape up any browned bits from the bottom of the skillet.
Let the mixture simmer 2 to 3 minutes so it reduces slightly.
Stir in the heavy cream and cream cheese cubes, then whisk or stir until the cream cheese melts and the sauce looks smooth.
If you want a thicker sauce, lightly sprinkle xanthan gum over the bubbling sauce while you whisk and cook 1 to 2 more minutes.

Step 5: Add the cheeses and chicken

Turn the heat to low and stir in half of the mozzarella and half of the Parmesan until they melt into the sauce.
Taste and adjust seasoning with extra salt and pepper if needed.
Return the browned chicken and any juices from the plate to the skillet and stir to coat every piece in the garlic mushroom sauce.
Sprinkle the remaining mozzarella and Parmesan evenly over the top.

Step 6: Bake the casserole

Transfer the skillet to the preheated oven.
Bake 15 to 20 minutes until the casserole bubbles around the edges and the cheese on top melts and turns lightly golden.
If the top browns too quickly, tent it loosely with foil.
If you want a deeper golden top, switch to broil for 1 to 2 minutes and watch closely.

Step 7: Rest and garnish

Remove the skillet from the oven and let the Keto Garlic Mushroom Chicken Casserole rest 5 to 10 minutes.
Sprinkle chopped fresh parsley over the top for color and freshness.
Scoop into bowls or plates and spoon extra sauce and mushrooms over each serving.

What to Serve with Keto Garlic Mushroom Chicken Casserole Recipe

This Keto Garlic Mushroom Chicken Casserole Recipe pairs nicely with simple sides that soak up the creamy sauce. I like it with roasted broccoli, sautéed green beans, or a quick side of garlicky spinach. Cauliflower rice, mashed cauliflower, or zucchini noodles also work well and keep the meal low carb. Add a crisp side salad with a tangy vinaigrette to balance the richness and you have a full dinner without much extra work.

Storage Options

Store leftovers in an airtight container in the fridge for up to 4 days.
Reheat single portions in the microwave at 50 to 60 percent power, stirring halfway so the sauce heats evenly.
Reheat larger portions in a covered baking dish at 325°F for 15 to 20 minutes until hot and bubbly.
Freeze cooled portions in freezer safe containers for up to 2 months, then thaw overnight in the fridge before reheating.