This Creamy Chicken and Spinach Casserole is a cozy, comforting dish that brings together tender chicken pieces, fresh spinach, and a rich, creamy sauce that just hugs everything perfectly. It’s easy to make and perfect for those days when you want something warm and satisfying without too much fuss.
I love this casserole because it feels like a warm hug in a dish. The creaminess from the sauce pairs so well with the slight earthiness of the spinach, and the chicken adds just the right amount of heartiness. It’s one of those meals that almost everyone enjoys, making it great for family dinners or casual get-togethers.
When I make this, I usually serve it with a simple side salad or some crusty bread to soak up all the creamy goodness. It’s also a fantastic leftover—the flavors develop even more and it reheats beautifully. If you’re looking for a dish that’s easy, tasty, and full of cozy vibes, this casserole is definitely a winner in my book.
Key Ingredients & Substitutions
Chicken: Cooked chicken breast works best because it stays tender and soaks up the creamy sauce nicely. Rotisserie chicken or leftovers are great shortcuts if you’re short on time.
Spinach: Fresh spinach gives a nice texture, but frozen spinach is a handy substitute—just be sure to thaw and squeeze out excess water to avoid a watery casserole.
Cheese: Mozzarella melts beautifully and gives gooeyness. Parmesan adds sharpness and depth. If you want a different flavor, try swapping Parmesan with Pecorino Romano or Asiago.
Dairy: Heavy cream creates a rich, smooth sauce. For a lighter dish, you can use half-and-half or whole milk, but the sauce may be less thick. Sour cream adds tang and creaminess, but Greek yogurt can work if you want a lighter option.
Seasonings: Italian seasoning is a simple mix that adds herb flavor. If you don’t have it, use a pinch of oregano, basil, and thyme. A little nutmeg brightens the sauce—don’t skip it if you want a cozy, full flavor.
How Can I Make the Creamy Sauce Thick and Smooth?
Creating a smooth cream sauce is key to this recipe and it starts with making a good roux to thicken the sauce:
- Melt butter in a saucepan over medium heat, then add chopped onions and garlic. Cook until soft but not browned.
- Stir in flour and cook for 1-2 minutes to remove the raw flour taste. This step is important for a thick sauce.
- Slowly whisk in the cream while stirring constantly to avoid lumps.
- Keep stirring until the sauce thickens and coats the back of a spoon.
- Remove from heat and stir in sour cream and seasonings to finish.
Tip: Use medium heat and stir well when adding cream to keep the sauce silky without curdling. Take your time and be patient—rushing can cause lumps or a runny sauce.
Equipment You’ll Need
- Oven-safe casserole dish – perfect for baking the whole dish evenly and serving straight from the oven.
- Large skillet – to wilt spinach and sauté onions and garlic easily in one pan.
- Medium saucepan – for making the creamy sauce without crowding.
- Whisk – helps keep the sauce smooth and lump-free when mixing flour and cream.
- Wooden spoon or spatula – great for stirring the sauce and folding in ingredients.
Flavor Variations & Add-Ins
- Swap chicken for cooked turkey or cooked sausage for a different protein twist that still pairs well with creamy sauce.
- Add sautéed mushrooms for an earthy note and extra texture.
- Mix in sun-dried tomatoes for a burst of tangy, sweet flavor.
- Use pepper jack cheese instead of mozzarella for a mild spicy kick.
Creamy Chicken and Spinach Casserole
Ingredients You’ll Need:
Main Ingredients:
- 3 cups cooked chicken breast, diced or shredded
- 10 oz fresh spinach (or 1 package frozen chopped spinach, thawed and drained)
- 2 cups shredded mozzarella cheese
- 1 cup grated Parmesan cheese
- 2 cups heavy cream (or half-and-half for lighter option)
- 1/2 cup sour cream
- 3 cloves garlic, minced
- 1 small onion, finely chopped
- 3 tablespoons butter
- 3 tablespoons all-purpose flour
- 1/2 teaspoon dried Italian seasoning (or a mix of basil, oregano, and thyme)
- Salt and freshly ground black pepper, to taste
- Optional: pinch of nutmeg for richness
How Much Time Will You Need?
This recipe takes about 15 minutes to prepare, plus 25-30 minutes baking time in the oven. Allow an extra 5 minutes for resting before serving, so plan for around 50 minutes total from start to finish.
Step-by-Step Instructions:
1. Preheat and Prepare:
First, preheat your oven to 375°F (190°C). Lightly grease a medium-sized casserole dish so the casserole won’t stick and will bake evenly.
2. Prepare the Spinach:
If you’re using fresh spinach, quickly wilt it in a large skillet over medium heat until just softened, then drain any extra liquid. For frozen spinach, make sure you thaw it well and squeeze out the moisture to avoid a watery casserole.
3. Make the Creamy Sauce:
In a saucepan over medium heat, melt the butter. Add the finely chopped onion and minced garlic, sautéing them for about 3-4 minutes until fragrant and translucent. Stir in the flour, cooking for 1-2 minutes while stirring constantly to form a smooth roux.
Slowly whisk in the heavy cream, stirring continuously to keep the sauce smooth. Continue stirring until it thickens nicely. Remove the saucepan from heat and stir in sour cream, Italian seasoning, nutmeg (if using), salt, and pepper for flavor.
4. Combine Ingredients and Assemble:
Add the cooked chicken, spinach, half of the mozzarella cheese, and half of the Parmesan cheese to the creamy sauce. Mix everything well to combine the flavors evenly.
Pour this mixture into your prepared casserole dish, spreading it out evenly.
5. Add Cheese Topping and Bake:
Sprinkle the remaining mozzarella and Parmesan cheese evenly on top. Bake uncovered in the oven for 25-30 minutes, or until the top is golden brown and bubbling.
6. Rest and Serve:
Once out of the oven, let the casserole sit for about 5 minutes to set slightly. This helps it hold together better when you serve. Enjoy your creamy, cheesy chicken and spinach casserole with a side salad or crusty bread!
Can I Use Frozen Chicken in This Casserole?
Yes, you can use frozen chicken, but make sure it’s fully thawed before cooking. Thaw it in the fridge overnight or use the defrost setting on your microwave. This helps ensure even cooking and the best texture.
Can I Substitute the Spinach with Other Greens?
Absolutely! Kale, Swiss chard, or collard greens can be great alternatives. Just sauté them until tender and drain any excess liquid before adding to the casserole to avoid sogginess.
How Do I Store Leftovers?
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven or microwave until warmed through. You can also freeze leftovers for up to 2 months; thaw fully before reheating.
Can I Make This Recipe Ahead of Time?
Yes, you can prepare the casserole up to step 8, then cover and refrigerate it for up to 24 hours. When ready, add the cheese topping and bake as directed. This makes meal prep super easy!
