When you’re following a keto lifestyle but craving real comfort food, this keto garlic mushroom chicken casserole delivers exactly what you need. Rich, creamy, and loaded with savory garlic and tender mushrooms, it proves that low-carb eating doesn’t mean sacrificing flavor or satisfaction. This casserole comes together in just 40 minutes and feels indulgent while keeping your macros in check.
The combination of earthy mushrooms, aromatic garlic, and melted cheese creates layers of flavor that make this dinner feel special, even on a regular Tuesday night. It’s the kind of meal that works for the whole family, whether they’re following keto or not. Nobody will miss the pasta or potatoes when the sauce is this creamy and the topping is golden and bubbling.
Why You’ll Love This Keto Garlic Mushroom Chicken Casserole
This casserole solves the biggest challenge of keto cooking: making meals that feel satisfying and complete without relying on starches. The heavy cream creates a luscious sauce that coats every bite, while the double cheese topping adds that irresistible golden crust you’d normally get from breadcrumbs or pasta.
The recipe is remarkably quick for a casserole, taking just 40 minutes from start to finish. Most of that is hands-off baking time, giving you space to prep sides or just relax. Sautéing the mushrooms first concentrates their flavor and prevents them from releasing excess moisture into the dish, which keeps the sauce creamy rather than watery.
The garlic and herb combination provides depth without overwhelming the dish, and both mozzarella and Parmesan bring different qualities—mozzarella for stretch and creaminess, Parmesan for sharp, nutty flavor. At just 385 calories and about 3-4 net carbs per serving, this fits perfectly into keto meal plans. It reheats beautifully, making it ideal for meal prep, and leftovers actually taste even better once the flavors have time to develop overnight.
Ingredients for Keto Garlic Mushroom Chicken Casserole
I keep these ingredients stocked because this casserole has become my go-to when I need something satisfying that won’t derail my macros. The ingredient list is short, but each component plays an important role in creating the rich, restaurant-quality flavor.
- 2 cups cooked chicken, shredded or diced
- 8 ounces mushrooms, sliced (button or cremini)
- 4 cloves garlic, minced
- 1 cup heavy cream
- 1 cup shredded mozzarella cheese
- 1/2 cup grated Parmesan cheese
- 1 tablespoon olive oil
- 1 teaspoon dried thyme
- 1 teaspoon dried oregano
- Salt and pepper to taste
- Fresh parsley, chopped, for garnish
Choosing Your Chicken: Rotisserie chicken is my favorite shortcut here—it’s already seasoned and saves time. One rotisserie chicken typically yields about 3 cups of meat, so you’ll have extra for another meal. If cooking chicken specifically for this recipe, season it well before cooking. I find that chicken thighs stay more tender in casseroles than breasts, though either works perfectly.
Mushroom Selection: Button mushrooms are mild and budget-friendly, while cremini (baby bella) mushrooms offer a deeper, earthier flavor. I prefer cremini for this recipe because their robust taste stands up to the rich cream and cheese. Avoid pre-sliced mushrooms if possible—whole mushrooms stay fresher and you can control the thickness of your slices. Clean them with a damp paper towel rather than rinsing under water, which makes them soggy.
About the Cream and Cheese: Full-fat heavy cream is essential for keto cooking and creates that luxurious sauce texture. Don’t substitute half-and-half or milk—they lack the fat content needed for proper keto macros and won’t create the same rich consistency. For the cheese, I always use freshly shredded mozzarella rather than pre-shredded. Pre-shredded cheese contains anti-caking agents that prevent it from melting as smoothly. Freshly grated Parmesan from a wedge has significantly more flavor than the shelf-stable variety.
How to Make Keto Garlic Mushroom Chicken Casserole
The key to this casserole is properly browning the mushrooms before assembling everything. Crowding them in the pan or skipping this step results in watery, bland mushrooms that compromise the whole dish.
Prepare and Sauté
Preheat your oven to 375°F and grease a 9×13-inch casserole dish. Heat the olive oil in a large skillet over medium heat until it shimmers slightly. Add your sliced mushrooms in a single layer—if they don’t fit comfortably, work in two batches. This matters because crowded mushrooms steam instead of brown. Let them cook undisturbed for 2-3 minutes to develop that golden color, then stir and continue cooking for another 3-4 minutes. You’ll know they’re ready when they’ve shrunk significantly, released their moisture, and developed nice caramelization. The pan should look dry, not pooling with liquid.
Add the minced garlic directly to the mushrooms and stir constantly for 1-2 minutes. Garlic burns quickly and turns bitter, so watch it carefully. Once it’s fragrant and just starting to turn golden, remove the skillet from the heat. This technique builds incredible flavor depth that carries through the entire dish.
Combine and Assemble
In a large mixing bowl, combine your cooked chicken with the sautéed mushroom-garlic mixture. Pour in the heavy cream, then add the thyme, oregano, salt, and pepper. I use about 1 teaspoon of salt and 1/2 teaspoon of pepper, but taste your mixture—rotisserie chicken is already salted, so you might need less. The herbs should be fragrant in the mixture but not overpowering. Fold everything together until the chicken and mushrooms are evenly coated in the herbed cream.
Transfer this mixture to your prepared casserole dish, spreading it into an even layer with a spatula. Make sure it reaches all corners of the dish so everything bakes evenly. Sprinkle the mozzarella cheese across the top first—it provides the creamy base layer. Then add the Parmesan over the mozzarella. The Parmesan will brown beautifully and create those crispy, golden bits that everyone fights over.
Bake to Golden Perfection
Slide the casserole into your preheated oven and bake for 25-30 minutes. You’re watching for the sauce to bubble around the edges and the cheese to melt completely and turn golden brown. If you want an extra-crispy, deeply browned top, switch your oven to broil for the last 2-3 minutes. Stay close during broiling—the difference between perfect and burned happens in seconds. The cheese should have dark golden patches but shouldn’t turn black.
Let the casserole rest for 5 minutes after removing it from the oven. This resting period allows the cream sauce to thicken slightly and makes serving much easier. Garnish with freshly chopped parsley for a pop of color and fresh flavor that brightens the rich dish.
What to Serve with Keto Garlic Mushroom Chicken Casserole
Since this casserole is already rich and complete, I pair it with lighter, vegetable-forward sides that add color and freshness without extra carbs.
Roasted Broccoli: Toss broccoli florets with olive oil, salt, and garlic powder, then roast at 425°F until the edges are crispy. The slight char and crunch contrast beautifully with the creamy casserole.
Simple Arugula Salad: Peppery arugula dressed with lemon juice, olive oil, and shaved Parmesan cuts through the richness perfectly. The acidity refreshes your palate between bites of the creamy main dish.
Cauliflower Mash: For those who miss mashed potatoes, cauliflower mash provides that comfort food element. Steam cauliflower until tender, then blend with butter, cream cheese, and garlic for a keto-friendly alternative.
Sautéed Green Beans: Quickly sauté green beans in butter with sliced almonds and a squeeze of lemon. The almonds add crunch and healthy fats while keeping carbs low.
Zucchini Noodles: Spiralized zucchini lightly sautéed in olive oil and garlic serves as a pasta substitute. The casserole sauce is perfect for coating the noodles.
Roasted Brussels Sprouts: Halve Brussels sprouts and roast with bacon pieces until caramelized. The slight bitterness and smoky bacon complement the creamy, garlicky casserole wonderfully.
Pro Tips & Variations
Maximize Mushroom Flavor: Choose cremini or even mix in some shiitake mushrooms for a more complex, umami-rich flavor. If you’re a mushroom lover, increase the amount to 12 ounces. Adding a splash of dry white wine to the mushrooms after they brown (before adding garlic) creates an even more sophisticated sauce.
Prevent Watery Casserole: The most common mistake is adding mushrooms that haven’t released their moisture. Always cook them until the pan looks dry. If your sauce seems thin after mixing, add 2 tablespoons of cream cheese to thicken it before baking.
Boost the Garlic: Four cloves provide good flavor, but if you’re a garlic enthusiast like me, go up to six. You can also add 1/2 teaspoon of garlic powder to the cream mixture for an extra layer of garlic flavor without adding bulk.
Cheese Variations: Gruyere instead of mozzarella creates a more sophisticated, nutty flavor. Adding 1/4 cup of cream cheese to the mixture makes it even creamier. For a sharper taste, use aged white cheddar in place of half the mozzarella.
Protein Swaps: Turkey works beautifully, especially after the holidays. Cooked and crumbled Italian sausage adds a completely different flavor profile. For a vegetarian keto version, replace chicken with diced firm tofu or additional mushrooms and add chopped spinach.
Add Vegetables: Spinach, kale, or diced zucchini fold in easily. If using spinach, add it to the warm mushroom mixture so it wilts before assembling. Sun-dried tomatoes provide bright, tangy pops of flavor throughout the dish.
Make It Spicier: Red pepper flakes in the mushroom sauté or a pinch of cayenne in the cream mixture adds pleasant heat. Pepper jack cheese instead of mozzarella gives it a kick.
Storage & Reheating Tips
I store leftovers in airtight containers in the refrigerator for up to 4 days. The flavors deepen overnight, making day-two servings even more delicious. This casserole freezes exceptionally well for up to 3 months. I prefer freezing individual portions in meal-prep containers so I can grab single servings whenever I need a quick keto dinner.
When reheating from the refrigerator, the microwave works fine for single portions—heat for 2-3 minutes, stirring halfway through to distribute heat evenly. For larger portions or the best texture, reheat covered in a 325°F oven for 20 minutes, then uncover and heat for an additional 5 minutes to re-crisp the cheese topping.
If reheating from frozen, thaw in the refrigerator overnight first, then reheat as you would refrigerated leftovers. The cream sauce might separate slightly during freezing and reheating—a quick stir once it’s heated through brings it back together. You can refresh the dish by adding a tablespoon of fresh cream and a sprinkle of cheese before reheating.
For meal prep, you can assemble the entire casserole without baking, cover tightly, and refrigerate for up to 24 hours before cooking. This makes weeknight dinners even easier—just pop it in the oven when you get home.
Common Questions
How many net carbs are in each serving? This casserole contains approximately 3-4 net carbs per serving, making it perfectly keto-friendly. The carbs come primarily from the mushrooms and small amounts in the cream and cheese. Using lower-carb vegetables or reducing mushrooms slightly decreases this further.
Can I use fresh herbs instead of dried? Yes, triple the amount when using fresh herbs. Add 1 tablespoon each of fresh thyme and oregano. Fresh herbs have more water content and milder flavor than dried, so you need more. Consider adding half to the mixture and half as a garnish for layered flavor.
What if I don’t have heavy cream? Coconut cream is the best dairy-free substitute and maintains the proper fat ratio for keto. Use full-fat canned coconut cream, not coconut milk. If you’re not dairy-free but out of heavy cream, mix equal parts butter and whole milk as a temporary substitute, though the texture won’t be quite as rich.
Can I use raw chicken instead of cooked? Absolutely. Dice raw chicken breasts or thighs into bite-sized pieces and cook them completely in the skillet before adding the mushrooms. Season them well with salt and pepper. Chicken thighs take about 6-8 minutes over medium heat, while breasts take 5-7 minutes. Make sure they reach 165°F internally.
How do I prevent the cheese from burning? If your oven runs hot or the top is browning too quickly, tent the casserole with foil after 15-20 minutes. This allows the inside to heat through while preventing the cheese from over-browning. Only broil at the end if you want extra crispiness and can watch it constantly.
This keto garlic mushroom chicken casserole proves that eating low-carb doesn’t mean settling for boring meals. The combination of tender chicken, savory mushrooms, and rich cream sauce satisfies cravings while keeping you on track. It’s become a weeknight staple in my kitchen because it delivers restaurant-quality flavor with minimal effort. Give this one a try when you need comfort food that works with your keto lifestyle.
Keto Garlic Mushroom Chicken Casserole
Ingredients
Equipment
Method
- Preheat oven to 375°F (190°C). Grease a 9×13-inch casserole dish with butter or cooking spray.
- Heat olive oil in a large skillet over medium heat. Add sliced mushrooms in a single layer and cook undisturbed for 2-3 minutes, then stir and continue cooking for 3-4 more minutes until golden brown and moisture has evaporated. The pan should look dry, not watery.
- Add minced garlic to the mushrooms and cook for 1-2 minutes, stirring constantly until fragrant. Be careful not to burn the garlic. Remove skillet from heat.
- In a large mixing bowl, combine the cooked chicken, sautéed mushrooms and garlic, heavy cream, dried thyme, dried oregano, salt (about 1 teaspoon), and pepper (about 1/2 teaspoon). Mix until everything is well combined and evenly coated.
- Transfer the chicken mixture to the prepared casserole dish, spreading it evenly across the bottom and into the corners.
- Sprinkle the shredded mozzarella cheese evenly over the chicken mixture, then top with the grated Parmesan cheese.
- Bake for 25-30 minutes until the sauce is bubbling around the edges and the cheese is melted and golden brown. For extra crispy topping, broil for 2-3 minutes at the end, watching carefully to prevent burning.
- Remove from oven and let rest for 5 minutes. The sauce will thicken slightly during this time. Garnish with freshly chopped parsley before serving.
