This Keto Chicken Mushroom Casserole brings cozy comfort without the carbs. It’s rich, creamy, and full of savory flavor, yet simple enough for a weeknight. You get juicy chicken, golden mushrooms, and a velvety sauce baked under a light layer of cheese.
Everything comes together in one dish, and the leftovers are even better the next day. If you’re craving comfort food that fits your goals, this one checks all the boxes.
Ingredients
Method
- Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.
- Sauté the mushrooms: Heat butter and olive oil in a large skillet over medium-high. Add sliced mushrooms and a pinch of salt. Cook 6–8 minutes, stirring occasionally, until golden and most liquid has evaporated.
- Add aromatics: Reduce heat to medium. Stir in the onion and cook 3–4 minutes until softened. Add the garlic and cook 30 seconds, just until fragrant.
- Build the sauce: Pour in the chicken broth and scrape up any browned bits from the pan. Stir in the heavy cream and bring to a gentle simmer.
- Melt in the cheeses: Add cream cheese in small chunks, stirring until smooth. Mix in the Parmesan, thyme, smoked paprika, and a few grinds of black pepper. Simmer 2–3 minutes to slightly thicken. Taste and adjust salt.
- Add greens (optional): Stir in the chopped spinach and cook 1–2 minutes until wilted.
- Combine with chicken: Fold the cooked chicken into the sauce until evenly coated.
- Assemble: Transfer the mixture to the prepared baking dish. Spread evenly and top with shredded mozzarella.
- Bake: Bake 18–22 minutes, until the casserole is bubbling and the cheese is melted and lightly golden.
- Rest and serve: Let it rest 5–10 minutes before serving so the sauce sets slightly. Sprinkle with extra thyme or chopped parsley if you like.
What Makes This Recipe So Good
- Low-carb comfort food: All the creamy, cheesy satisfaction without pasta or flour.
- One-dish convenience: Minimal prep, easy cleanup, and great for meal prep.
- Balanced flavors: Earthy mushrooms, savory garlic, and thyme bring depth to the creamy sauce.
- Flexible: Works with rotisserie chicken, leftover turkey, or even sautéed ground chicken.
- Family-friendly: It’s rich and familiar, so even non-keto eaters enjoy it.
What You’ll Need
- Chicken: 4 cups cooked, shredded or cubed (rotisserie chicken works great)
- Mushrooms: 16 ounces cremini or baby bella, sliced
- Butter: 3 tablespoons
- Olive oil: 1 tablespoon
- Onion: 1 small, finely chopped
- Garlic: 3 cloves, minced
- Heavy cream: 1 cup
- Chicken broth: 1/2 cup, low-sodium
- Cream cheese: 4 ounces, softened
- Parmesan: 1/2 cup, finely grated
- Mozzarella: 1 cup, shredded (for topping)
- Thyme: 1 teaspoon dried or 1 tablespoon fresh, chopped
- Smoked paprika: 1/2 teaspoon (optional, adds warmth)
- Spinach: 2 cups fresh, roughly chopped (optional but great for texture and color)
- Salt and pepper: To taste
- Cooking spray or extra butter: For greasing the baking dish
Step-by-Step Instructions
- Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
- Sauté the mushrooms: Heat butter and olive oil in a large skillet over medium-high.
Add sliced mushrooms and a pinch of salt. Cook 6–8 minutes, stirring occasionally, until golden and most liquid has evaporated.
- Add aromatics: Reduce heat to medium. Stir in the onion and cook 3–4 minutes until softened.
Add the garlic and cook 30 seconds, just until fragrant.
- Build the sauce: Pour in the chicken broth and scrape up any browned bits from the pan. Stir in the heavy cream and bring to a gentle simmer.
- Melt in the cheeses: Add cream cheese in small chunks, stirring until smooth. Mix in the Parmesan, thyme, smoked paprika, and a few grinds of black pepper.
Simmer 2–3 minutes to slightly thicken. Taste and adjust salt.
- Add greens (optional): Stir in the chopped spinach and cook 1–2 minutes until wilted.
- Combine with chicken: Fold the cooked chicken into the sauce until evenly coated.
- Assemble: Transfer the mixture to the prepared baking dish. Spread evenly and top with shredded mozzarella.
- Bake: Bake 18–22 minutes, until the casserole is bubbling and the cheese is melted and lightly golden.
- Rest and serve: Let it rest 5–10 minutes before serving so the sauce sets slightly.
Sprinkle with extra thyme or chopped parsley if you like.
How to Store
- Refrigerator: Cool completely, then cover tightly. Store up to 4 days.
- Freezer: Portion into freezer-safe containers and freeze up to 2 months. Thaw overnight in the fridge before reheating.
- Reheat: Warm individual portions in the microwave in 45–60 second bursts, stirring between, or reheat covered in a 325°F (165°C) oven until hot.
Add a splash of broth or cream if it looks dry.
Why This is Good for You
- High in protein: Chicken supports muscle maintenance and keeps you full.
- Healthy fats: Cream and cheese help keep carbs low while adding satiety.
- Nutrient-rich mushrooms: Provide B vitamins, selenium, and a savory umami kick.
- Low-carb profile: No flour or pasta, so it fits keto and low-carb plans easily.
What Not to Do
- Don’t overcrowd the mushrooms: They’ll steam instead of brown. Use a large skillet and cook in batches if needed.
- Don’t skip tasting the sauce: Adjust salt and seasoning before baking for the best flavor.
- Don’t use fat-free dairy: It won’t melt the same and often contains added starches.
- Don’t bake too long: Overbaking can make the sauce greasy and the chicken dry. Pull it when it’s bubbling and lightly golden.
Variations You Can Try
- Bacon mushroom twist: Cook 4–6 slices of bacon until crisp, crumble, and stir into the casserole.
Use a spoonful of bacon fat to sauté the mushrooms.
- Broccoli cheddar version: Swap spinach for 2 cups of lightly steamed broccoli florets and use sharp cheddar in place of mozzarella.
- Herb-forward: Replace thyme with a mix of rosemary and parsley, and add a squeeze of lemon to brighten the sauce.
- Spicy kick: Add red pepper flakes or a diced jalapeño with the onions. Pepper jack cheese works well here.
- Dairy-light option: Replace half the heavy cream with unsweetened almond milk and add 1/2 teaspoon xanthan gum to thicken, whisking well.
- Turkey swap: Use leftover roasted turkey instead of chicken—perfect after the holidays.
FAQ
Can I use raw chicken instead of cooked?
Yes, but cook it first. Sauté bite-sized pieces in a little oil and salt until just cooked through, then proceed with the recipe.
Starting with cooked chicken keeps the baking time shorter and the texture better.
What mushrooms work best?
Cremini or baby bella mushrooms have great flavor and hold up well. White button mushrooms work too, and sliced portobello can add a meatier bite. Just be sure to cook off their moisture so the sauce doesn’t get watery.
Is this casserole gluten-free?
Yes.
There’s no flour or pasta, and the sauce thickens with cream, cream cheese, and Parmesan. Always check your broth and seasonings to make sure they’re gluten-free.
How many carbs per serving?
It varies based on brands and add-ins, but a typical serving lands around 5–7 net carbs. Using spinach and low-carb broth keeps the count down.
If you need exact numbers, plug your ingredients into a nutrition calculator.
Can I make it ahead?
Absolutely. Assemble the casserole up to the cheese topping, cover, and refrigerate for up to 24 hours. Add 5–10 extra minutes to the bake time if starting from cold.
What can I serve with it?
Steamed green beans, garlicky sautéed zucchini, or a simple side salad with a tangy vinaigrette pair nicely.
Cauliflower rice is also great for soaking up the sauce.
Why did my sauce separate?
That usually happens from high heat or overbaking. Keep the stovetop heat to a gentle simmer and pull the casserole once it’s bubbling around the edges. If it looks slightly broken, stir in a tablespoon of cream when reheating.
Final Thoughts
This Keto Chicken Mushroom Casserole delivers big comfort with simple steps and everyday ingredients. It’s creamy, savory, and adaptable to whatever you have on hand. Make it once, and it’ll become a reliable weeknight favorite—or a crowd-pleaser for casual gatherings. Keep it in your rotation for an easy, satisfying meal that supports your low-carb goals.
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