A creamy, cheesy low-carb chicken casserole loaded with tender chicken, earthy mushrooms, fresh spinach, garlic, and Parmesan. It’s comforting, high in protein, and easy to prepare for a weeknight dinner or meal prep.
Recipe Details
Prep Time: 15 minutes
Cook Time: 30–35 minutes
Total Time: 45–50 minutes
Servings: 6
Course: Dinner
Cuisine: Low-Carb / American
Difficulty: Easy
Net Carbs: Approximately 5–7 g per serving, depending on ingredients
Ingredients
Chicken
1½ lb (680 g) boneless, skinless chicken breasts
1 tablespoon olive oil
1 teaspoon paprika
1 teaspoon Italian seasoning
½ teaspoon garlic powder
½ teaspoon onion powder
½ teaspoon salt
¼ teaspoon black pepper
Vegetables
8 oz (225 g) mushrooms, sliced
4 cups fresh spinach
½ medium yellow onion, finely diced
3 cloves garlic, minced
1 tablespoon olive oil or butter
Creamy Sauce
4 oz (115 g) cream cheese, softened
½ cup heavy cream
½ cup chicken broth
½ cup grated Parmesan cheese
½ teaspoon Italian seasoning
¼ teaspoon garlic powder
¼ teaspoon black pepper
¼ teaspoon salt, or to taste
½ cup shredded mozzarella cheese
Optional Garnish
2 tablespoons fresh parsley
1 tablespoon grated Parmesan
Freshly cracked black pepper
Red pepper flakes
A squeeze of fresh lemon juice
Instructions
- Preheat the Oven
Preheat your oven to 375°F (190°C).
Lightly grease a 9×13-inch baking dish or similar-sized casserole dish.
- Prepare the Chicken
Pat the chicken breasts dry with paper towels.
If the breasts are very thick, slice them horizontally into thinner cutlets. This helps them cook evenly and prevents the outside from drying out before the center is done.
Season both sides with:
paprika
Italian seasoning
garlic powder
onion powder
salt
black pepper
3. Sear the Chicken
Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add the chicken and cook for approximately 3–4 minutes per side, just until golden brown.
The chicken doesn’t need to be fully cooked yet because it will finish cooking in the oven.
Transfer the chicken to a plate.
- Cook the Mushrooms
Using the same skillet, add another tablespoon of olive oil or butter.
Add the sliced mushrooms.
Cook for 5–7 minutes, stirring occasionally, until the mushrooms release their moisture and become golden brown.
Don’t rush this step—the browning gives the casserole much more flavor.
- Add Onion, Garlic & Spinach
Add the diced onion to the mushrooms.
Cook for 2–3 minutes.
Add the minced garlic and cook for about 30 seconds.
Add the fresh spinach in handfuls.
Cook for 1–2 minutes, stirring, until the spinach wilts.
Remove the skillet from the heat.
6. Make the Creamy Sauce
In a bowl, combine:
softened cream cheese
heavy cream
chicken broth
Parmesan
Italian seasoning
garlic powder
black pepper
salt
Whisk until mostly smooth.
A few small cream-cheese lumps are fine—they will melt during baking.
- Assemble the Casserole
Spread the mushroom and spinach mixture evenly across the bottom of the prepared baking dish.
Place the seared chicken breasts on top.
Pour the creamy Parmesan sauce evenly over the chicken and vegetables.
Sprinkle the shredded mozzarella over the top.
- Bake
Cover the dish loosely with aluminum foil.
Bake at 375°F (190°C) for 20 minutes.
Remove the foil and bake for another 8–12 minutes, until the cheese is melted and bubbling and the chicken reaches an internal temperature of 165°F (74°C).
For a more golden cheese topping, switch to broil for 1–2 minutes, watching carefully.
- Rest
Remove the casserole from the oven and let it rest for 5–10 minutes.
This allows the sauce to thicken slightly and makes the chicken easier to slice.
- Garnish & Serve
Sprinkle with fresh parsley and additional Parmesan.
For extra brightness, add a small squeeze of fresh lemon juice.
Serve warm.
Tips for the Best Chicken Bake
Don’t overcook the chicken
Chicken breast can become dry quickly. Use a meat thermometer and remove it when the thickest part reaches 165°F (74°C).
Brown the mushrooms well
Cooking the mushrooms until their excess moisture evaporates prevents a watery casserole.
Use softened cream cheese
Room-temperature cream cheese blends into the sauce much more easily.
Don’t skip the resting time
The sauce thickens as it cools slightly.
For extra flavor
Add a pinch of red pepper flakes or a little smoked paprika to the sauce.
Low-Carb Variations
Broccoli Chicken Bake
Replace half of the mushrooms with 2 cups steamed broccoli.
Bacon Chicken Bake
Add 4–6 slices cooked and crumbled bacon before baking.
Buffalo Chicken Bake
Add ¼ cup buffalo sauce to the creamy sauce and use cheddar instead of mozzarella.
Italian Chicken Bake
Add:
chopped sun-dried tomatoes
basil
oregano
mozzarella
Parmesan
Extra-Cheesy Version
Use:
½ cup mozzarella
½ cup Parmesan
¼ cup shredded cheddar
What to Serve With It
Keep the meal low-carb by serving it with:
cauliflower rice
roasted broccoli
zucchini noodles
asparagus
green beans
cauliflower mash
simple leafy green salad
roasted Brussels sprouts
Storage & Meal Prep
Refrigerator
Store leftovers in an airtight container for 3–4 days.
Reheating
Reheat individual portions in the microwave for 1–2 minutes, or until hot.
For oven reheating, cover with foil and warm at 350°F (175°C) until heated through.
Add a splash of chicken broth or cream if the sauce becomes too thick.
Freezing
You can freeze the cooked casserole for up to 2 months.
For best texture, thaw overnight in the refrigerator before reheating.
Approximate Nutrition
Per serving, based on 6 servings:
Calories: ~390–430
Protein: ~43–47 g
Fat: ~22–25 g
Total Carbohydrates: ~7–9 g
Fiber: ~1–2 g
Net Carbs: ~5–7 g
Nutrition is an estimate and varies according to the specific chicken, cheese, cream, and vegetables used.
Recipe Q&A
Is this recipe keto-friendly?
Yes. The basic recipe is low in carbohydrates and can fit a keto-style meal plan, provided your specific ingredients fit your carbohydrate target.
Is this recipe gluten-free?
The ingredients listed are naturally gluten-free, but always check packaged chicken broth, seasonings, cream cheese, and other processed ingredients for gluten or cross-contact warnings.
Can I use chicken thighs?
Absolutely. Boneless, skinless chicken thighs work particularly well and stay very juicy.
Can I use frozen spinach?
Yes. Thaw it completely and squeeze out excess water before adding it. Otherwise, the casserole may become watery.
Can I use frozen mushrooms?
Fresh mushrooms are preferable, but frozen mushrooms can work. Thaw and drain them thoroughly before cooking.
Can I substitute half-and-half for heavy cream?
Yes, but the sauce will be slightly less rich and may be a little thinner.
Can I make it without cream cheese?
Yes. Replace the cream cheese with approximately ¾ cup additional heavy cream and ¼ cup extra Parmesan. The texture will be different but still creamy.
Can I use cheddar instead of mozzarella?
Yes. Cheddar gives the casserole a stronger, sharper flavor.
Can I add bacon?
Definitely. Crispy bacon pairs beautifully with chicken, spinach, and mushrooms.
How do I prevent the casserole from becoming watery?
The biggest trick is to cook the mushrooms until their liquid has evaporated and squeeze excess water from frozen spinach.
Can I prepare this ahead of time?
Yes. Assemble the casserole, cover it, and refrigerate for up to 24 hours. Add about 5–10 minutes to the baking time if starting from cold.
Can I use rotisserie chicken?
Yes. Use approximately 3–4 cups shredded cooked chicken. Since the chicken is already cooked, reduce the baking time to about 20–25 minutes, just until the casserole is hot and bubbly.
What other cheese can I use?
Good choices include:
mozzarella
provolone
Monterey Jack
cheddar
Gruyère
Parmesan
Can I add more vegetables?
Yes. Zucchini, broccoli, asparagus, bell peppers, and cauliflower are excellent low-carb additions.
How do I make it spicy?
Add ½ teaspoon red pepper flakes, diced jalapeño, or a little hot sauce to the creamy sauce.
Can I make this dairy-free?
Yes, but you’ll need dairy-free substitutes for the cream cheese, heavy cream, Parmesan, and mozzarella. Choose unsweetened products designed for savory cooking.
Is this good for meal prep?
Yes. Divide the finished casserole into individual containers and refrigerate for up to 3–4 days. It reheats especially well and makes an easy high-protein lunch or dinner.
