Keto Garlic Mushroom Chicken Casserole The Low-Carb Comfort Dish That Melts Every Doubter

I’ll be honest: I make casseroles when I want dinner that feels fancy but doesn’t require babysitting. This Keto Garlic Mushroom Chicken Casserole hits that sweet spot.

It layers tender chicken, earthy mushrooms, and a creamy garlic sauce, then bakes until golden and bubbly. Best part? It stays low-carb without sacrificing comfort. Want to impress guests or just treat yourself after a long day? This will do the trick.

Why this casserole works (and why you’ll love it)

I tested several versions before landing on this one. I used boneless skinless chicken thighs for juiciness, but breasts work if you prefer leaner meat. I swapped flour for almond flour and a touch of cream cheese to thicken, so the sauce stays rich without carbs.

The mushrooms release savory juices that deepen the sauce, so you don’t miss pasta or potatoes.

Why not just buy a frozen casserole? Because homemade wins on taste and you control the ingredients. Also, you get bragging rights. Who doesn’t want that? 😉

Ingredients — simple, low-carb, high-flavor

Serves 4–6

• 2 lbs boneless skinless chicken thighs (cut into 1-inch pieces) — or 3 large chicken breasts

• 12 oz cremini or button mushrooms, sliced

• 4 tbsp butter, divided (2 for searing, 2 for sauce)

• 4 cloves garlic, minced (plus 1 extra clove for final garnish if you’re dramatic)

• 1 medium onion, finely chopped

• 1 cup heavy cream

• 4 oz cream cheese, cubed and softened

• 1/2 cup grated Parmesan (plus extra for topping)

• 1/2 cup chicken broth

• 1/3 cup almond flour (thickener, low-carb)

• 2 tsp Dijon mustard

• 1 tsp smoked paprika

• Salt and pepper, to taste

• Fresh thyme or parsley, chopped for garnish

Key swaps & notes

• Replace heavy cream with full-fat coconut milk for dairy-free; skip Parmesan.

• Use arrowroot or coconut flour only if you track carbs carefully; almond flour remains best keto option.

• If you prefer milder garlic, reduce to 3 cloves.

Equipment & prep

• Oven-safe skillet or a 9×13 baking dish. I prefer a cast-iron skillet for searing then popping it straight into the oven.

• Preheat oven to 375°F (190°C).

• Pat chicken dry and season generously. Dry meat sears better and builds more flavor.

Step-by-step — make it without stress

Sear the chicken

1. Heat 2 tbsp butter over medium-high heat until it foams. Add chicken pieces in a single layer. Sear 2–3 minutes per side until browned. Don’t crowd the pan. Work in batches if needed.

2. Transfer the chicken to a plate. It will finish cooking in the oven.

Sauté the veggies

1. Lower heat to medium and add the remaining 2 tbsp butter. Sauté the chopped onion for 2 minutes until soft.

2. Add the sliced mushrooms and cook 5–6 minutes until they release moisture and brown. Stir in the minced garlic and cook 30 seconds until fragrant.

Build the creamy garlic sauce

1. Pour 1/2 cup chicken broth into the pan and scrape up browned bits. Those bits lift all the flavor.

2. Add heavy cream, cream cheese, Dijon, smoked paprika, and almond flour. Stir until cream cheese melts and sauce thickens slightly.

3. Stir in 1/2 cup Parmesan and season with salt and pepper. Taste and adjust—this dish rewards a bold hand with salt.

Assemble and bake

1. Return the seared chicken to the skillet and stir to coat with sauce. Or transfer everything into a greased baking dish and pour sauce evenly.

2. Sprinkle extra Parmesan on top for a golden crust. Bake 20–25 minutes at 375°F until the chicken reaches 165°F internal and the top bubbles. If you want a broiled finish, blast under the broiler for 2–3 minutes — watch it so it doesn’t burn.

Serving suggestions (keep it keto)

• Serve over cauliflower rice or zoodles to catch every drop of sauce.

• Add a side of garlic green beans or a crisp mixed greens salad with lemon vinaigrette to cut richness.

• For a cozy bowl, spoon over mashed cauliflower and top with fresh thyme.

Nutrition & keto friendliness

This casserole focuses on fat and protein while keeping carbs minimal. Almond flour and mushrooms provide only a few grams of net carbs per serving. If you want exact macros, weigh your ingredients — I recommend tracking apps like MyFitnessPal for precise numbers. FYI, this dish makes great leftovers.

Tips, tricks, and troubleshooting

• Overly thin sauce? Simmer a few extra minutes to reduce, or stir in another tablespoon of almond flour mixed with a little water.

• Sauce too thick? Add a splash of chicken broth or cream and stir.

• Mushrooms release too much water? Cook them longer over medium-high heat before adding cream so liquid reduces.

• Chicken dry after baking? Use thighs or avoid overcooking — check earlier. Thighs forgive more.

Variations you’ll actually use

• Spinach & artichoke twist: Fold in 2 cups fresh spinach and 1/2 cup chopped artichoke hearts before baking.

• Cheesy herb: Add shredded mozzarella or Gruyère for an oozy top.

• Spicy garlic: Add 1/4 tsp red pepper flakes or a dash of hot sauce to the sauce for heat.

• One-pan slow-cooker: Brown chicken, then transfer everything to a slow cooker and cook on low 3–4 hours. Add cream cheese near the end.

Make-ahead & storage

• Prep in advance: Sear chicken and prepare sauce the day before. Assemble and refrigerate, then bake when ready.

• Store: Keep in an airtight container for up to 3–4 days.

• Freeze: Freeze in a casserole dish or airtight container for up to 3 months. Thaw overnight in fridge and reheat slowly in oven at 325°F.

Pairings & wine (for non-keto guests)

• Pair with a crisp Chardonnay or Sauvignon Blanc for brightness. If you serve non-keto sides, consider a light-bodied red like Pinot Noir. IMO, the creaminess begs for a white.

Why almond flour beats regular flour here

Almond flour thins and thickens nicely without adding carbs. It also gives the sauce a slightly nutty background note that pairs with mushrooms. Regular wheat flour would add unnecessary carbs and change texture.

Final plating & garnish

Sprinkle chopped fresh parsley or thyme and a tiny lemon zest for a bright finish. Add a few roasted garlic cloves on top if you want to dial up the garlic party. Presentation matters: serve in shallow bowls so guests can spoon sauce over everything.

FAQs

Q: Can I use chicken breasts instead of thighs?
A: Yes. Slice into even pieces and watch cooking time to avoid drying. Consider brining breasts for 20 minutes to keep them juicy.

Q: Is this dish dairy-free possible?
A: Yes. Substitute cream with full-fat coconut milk and use dairy-free cheese alternatives. The flavor shifts but stays comforting.

Q: How many carbs per serving?
A: Rough estimate: 3–6g net carbs per serving depending on almond flour brand and portion size. Track ingredients for exact counts.

Q: Can I make this stovetop only?
A: Definitely. Simmer everything in the skillet until chicken finishes cooking and sauce thickens. Finish with a quick broil if you like a crisp top.

Q: How do I add more veggies?
A: Fold in chopped bell peppers, zucchini, or spinach before baking. Reduce oven time slightly for tender veggies.