Keto Cheesy Pesto Chicken & Mushroom Casserole – Comforting, Creamy, And Low-Carb
This casserole is the kind of weeknight win you keep on repeat. Tender chicken, garlicky mushrooms, and creamy pesto sauce all baked under a bubbly layer of cheese—it’s rich, cozy, and surprisingly simple. Everything comes together in one pan with everyday ingredients.
It’s low in carbs without feeling “diet,” and it reheats beautifully. If you want something satisfying that doesn’t ask much of you, this is it.
Keto Cheesy Pesto Chicken & Mushroom Casserole - Comforting, Creamy, And Low-Carb
Ingredients
Method
- Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish. Pat chicken dry and season generously with salt and pepper.
- Sear the chicken: Heat 1 tablespoon oil in a large skillet over medium-high. Add chicken in a single layer and sear 2–3 minutes per side until lightly golden. It doesn’t need to be fully cooked. Transfer to the baking dish.
- Sauté aromatics: In the same skillet, add remaining oil and the butter. Add onion (if using) and cook 2–3 minutes until soft. Stir in garlic and cook 30 seconds until fragrant.
- Cook the mushrooms: Add sliced mushrooms, a pinch of salt, and cook 5–7 minutes, stirring occasionally, until browned and most moisture has evaporated.
- Build the sauce: Lower heat to medium. Stir in cream cheese until melted and smooth. Add heavy cream, chicken broth, and pesto. Simmer 2–3 minutes, stirring, until slightly thickened. Season with salt, pepper, and a pinch of red pepper flakes. Add lemon juice if you like a brighter note.
- Combine: Pour the mushroom pesto cream sauce over the chicken in the baking dish. Gently toss to coat and spread evenly.
- Top with cheese: Sprinkle mozzarella (or provolone) over the top. Finish with grated Parmesan for extra depth.
- Bake: Bake uncovered for 18–22 minutes, until the cheese is melted and bubbly and the chicken reaches 165°F (74°C).
- Brown the top (optional): Broil 1–2 minutes for golden, blistered cheese. Watch closely.
- Rest and serve: Let the casserole rest 5 minutes to set. Garnish with chopped basil or parsley. Serve as is or with a simple side.
What Makes This Recipe So Good
- Big flavor, small effort: Store-bought pesto does the heavy lifting while the oven handles the rest.
- Keto-friendly and filling: High in protein and fat, low in carbs, and genuinely satisfying.
- One-pan convenience: Sear on the stovetop, then bake to finish—less cleanup, more flavor.
- Family-approved: Creamy sauce and melty cheese make it a crowd-pleaser, keto or not.
- Flexible: Swap veggies, cheeses, or proteins to match what you have.
Shopping List
- Chicken: 1.5 to 2 pounds boneless, skinless chicken thighs or breasts, cut into bite-size pieces
- Mushrooms: 12 ounces cremini or button mushrooms, sliced
- Pesto: 1/2 cup basil pesto (store-bought or homemade), look for one made with olive oil
- Cream: 3/4 cup heavy cream
- Cream cheese: 4 ounces, cubed and softened
- Cheese for topping: 1 to 1 1/2 cups shredded mozzarella or provolone
- Parmesan: 1/4 cup grated, for extra punch
- Garlic: 3 cloves, minced
- Onion or shallot: 1 small, finely diced (optional but tasty)
- Olive oil or avocado oil: 2 tablespoons
- Butter: 1 tablespoon (for mushrooms)
- Chicken broth: 1/3 cup (low-sodium)
- Seasonings: Salt, black pepper, red pepper flakes (optional)
- Fresh lemon juice: 1 to 2 teaspoons (optional, brightens the sauce)
- Fresh basil or parsley: For garnish (optional)
Instructions
- Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
Pat chicken dry and season generously with salt and pepper.
- Sear the chicken: Heat 1 tablespoon oil in a large skillet over medium-high. Add chicken in a single layer and sear 2–3 minutes per side until lightly golden. It doesn’t need to be fully cooked.
Transfer to the baking dish.
- Sauté aromatics: In the same skillet, add remaining oil and the butter. Add onion (if using) and cook 2–3 minutes until soft. Stir in garlic and cook 30 seconds until fragrant.
- Cook the mushrooms: Add sliced mushrooms, a pinch of salt, and cook 5–7 minutes, stirring occasionally, until browned and most moisture has evaporated.
- Build the sauce: Lower heat to medium.
Stir in cream cheese until melted and smooth. Add heavy cream, chicken broth, and pesto. Simmer 2–3 minutes, stirring, until slightly thickened.
Season with salt, pepper, and a pinch of red pepper flakes. Add lemon juice if you like a brighter note.
- Combine: Pour the mushroom pesto cream sauce over the chicken in the baking dish. Gently toss to coat and spread evenly.
- Top with cheese: Sprinkle mozzarella (or provolone) over the top.
Finish with grated Parmesan for extra depth.
- Bake: Bake uncovered for 18–22 minutes, until the cheese is melted and bubbly and the chicken reaches 165°F (74°C).
- Brown the top (optional): Broil 1–2 minutes for golden, blistered cheese. Watch closely.
- Rest and serve: Let the casserole rest 5 minutes to set. Garnish with chopped basil or parsley.
Serve as is or with a simple side.
Keeping It Fresh
- Storage: Cool completely, then refrigerate in an airtight container for up to 4 days.
- Reheating: Warm individual portions in the microwave at 50–60% power to prevent separation. For best texture, reheat in a 325°F oven, covered, for 10–15 minutes.
- Freezing: Freeze tightly wrapped portions for up to 2 months. Thaw overnight in the fridge, then reheat gently.
Stir the sauce after reheating if it looks slightly separated—it will come back together.
Benefits of This Recipe
- Keto-aligned macros: Low-carb, high-fat, and moderate protein helps support ketosis and steady energy.
- Nutrient-rich ingredients: Mushrooms add B vitamins and minerals; pesto brings healthy fats from olive oil and nuts.
- Meal-prep friendly: Holds up well for several days and tastes even better the next day.
- Comfort without the crash: Creamy and cheesy but won’t spike carbs like pasta or rice.
What Not to Do
- Don’t skip seasoning the chicken: Salting the meat directly builds flavor from the start.
- Don’t overcrowd the skillet: Sear in batches if needed. Crowding steams the chicken and mushrooms.
- Don’t use watery pesto: Oil-based pesto works best. Watery or low-fat versions can break the sauce.
- Don’t boil the cream hard: Keep it to a gentle simmer.
A rolling boil can cause separation.
- Don’t overbake: Pull it as soon as the cheese is bubbly and the chicken is done to keep it tender.
Alternatives
- Protein swaps: Use turkey, rotisserie chicken (stir in at step 6), or shrimp. For shrimp, skip the initial bake and cook just until pink.
- Veggie options: Add spinach, zucchini ribbons, or asparagus tips. Sauté briefly to remove excess moisture before adding.
- Dairy tweaks: Sub half-and-half for a lighter sauce (not as thick).
Try fontina or gruyère for a nuttier melt.
- Dairy-free path: Use coconut cream and a dairy-free pesto and cheese alternative. Flavor will shift slightly sweeter; add extra lemon and salt.
- Nut-free pesto: Choose a pesto made without pine nuts or make your own with pumpkin seeds or sunflower seeds.
- Extra-low carb: Skip the onion, and use more mushrooms and spinach to keep carbs minimal.
FAQ
Can I use frozen mushrooms?
Yes, but thaw and drain them well, then sauté until most moisture cooks off. Otherwise, the sauce may turn thin and watery.
Is store-bought pesto really okay for keto?
Absolutely.
Just check the label for added sugars or cheap oils. Look for pesto made with olive oil and no fillers.
Can I make this ahead?
You can assemble the casserole up to the cheese step, cover, and refrigerate for 24 hours. Add 5–8 extra minutes to bake time since it’ll be cold.
What can I serve with it?
It’s great with a crisp green salad, roasted broccoli, sautéed zucchini, or cauliflower rice.
Keep sides simple so the rich sauce can shine.
How do I thicken the sauce without starch?
The cream cheese and gentle simmering do the job. If you want it thicker, reduce the sauce a minute or two longer, or add a small handful of extra mozzarella to melt in.
Can I make it spicy?
Yes. Add red pepper flakes to the sauce and a pinch of cayenne when seasoning the chicken.
You can also use a spicy pesto if you find one.
Why did my sauce separate?
It usually happens from high heat or low-fat ingredients. Keep the simmer gentle, use full-fat dairy, and whisk as you add cream and cream cheese.
Wrapping Up
Keto Cheesy Pesto Chicken & Mushroom Casserole is a reliable, repeatable dinner with bold flavor and minimal fuss. It covers the comfort food craving without the carbs, and it’s flexible enough for whatever’s in your fridge.
Make it once on a weeknight, and it’ll likely join your regular rotation. Warm, creamy, and packed with savory goodness—this is the kind of dish that makes eating low-carb feel easy.
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