This Creamy Chicken and Spinach Casserole is a warm, comforting dish packed with tender chicken, fresh spinach, and a rich, creamy sauce that makes every bite feel like a hug. It’s the kind of meal that’s both hearty and gentle, with the spinach adding a nice pop of green and a little freshness to balance the creaminess.
I love making this casserole when I want something easy but satisfying. It comes together quickly and bakes into this bubbling dish that’s creamy on the inside and golden on top. I often add a little extra cheese on top for that perfect gooey layer that everyone always fights over. It’s one of those recipes that feels like a special treat but is simple enough for a weeknight dinner.
My favorite way to serve it is right out of the oven with a side of crusty bread to soak up all the creamy sauce. It’s also great for leftovers because the flavors deepen overnight. This casserole has become a family favorite, especially on colder nights when we all need a bit of comfort in our bowls. I bet you’ll want to keep this recipe handy for those cozy evenings too.
Key Ingredients & Substitutions
Chicken breasts: I like using boneless, skinless breasts for quick cooking. You can swap with thighs for more flavor and moistness.
Spinach: Fresh spinach gives a bright taste. Frozen works too—just thaw and squeeze out extra water to avoid a watery casserole.
Heavy cream and milk: These create the creamy sauce. For a lighter version, use half-and-half or a mix of milk and Greek yogurt, but keep watch on thickness.
Parmesan and mozzarella cheeses: Parmesan adds sharpness; mozzarella melts beautifully. You can try cheddar or Monterey Jack for a different twist.
Flour: This makes the sauce thick. If gluten-free, use cornstarch or a gluten-free flour blend in the same amount.
How Do You Make the Creamy Sauce Without Lumps?
Making a smooth sauce is key. Here’s how I do it:
- Heat butter, sauté garlic and onion until soft.
- Sprinkle flour evenly, stir constantly to cook it but don’t let it brown.
- Add cream and milk slowly while whisking to stop lumps.
- Keep stirring until sauce thickens, then add cheese last to melt smoothly.
Patience and constant stirring help the sauce become silky and rich without any grainy bits.
Equipment You’ll Need
- Large skillet – perfect for searing chicken and cooking the creamy sauce in one pan.
- Whisk – helps keep your sauce smooth and lump-free when adding flour and cream.
- Wooden spoon or spatula – great for stirring the spinach and chicken without scratching your pan.
- Casserole dish (about 9×13 inches) – roomy enough for baking the whole dish evenly and getting a golden cheese top.
- Measuring cups and spoons – to ensure your cream, milk, and seasonings are just right.
Flavor Variations & Add-Ins
- Swap chicken for cooked turkey or ham for a tasty change, especially after holidays.
- Add sautéed mushrooms or sun-dried tomatoes for extra depth and texture.
- Mix in shredded fontina or gouda cheese for a different but delicious creamy flavor.
- Stir in red pepper flakes or smoked paprika if you want a little warmth and spice.
Creamy Chicken and Spinach Casserole
Ingredients You’ll Need:
- 2 lbs (about 900g) boneless, skinless chicken breasts, cut into chunks
- 1 tbsp olive oil
- Salt and pepper, to taste
- 3 tbsp unsalted butter
- 3 cloves garlic, minced
- 1 small onion, finely chopped
- 10 oz (280g) fresh spinach, roughly chopped (or frozen spinach, thawed and drained)
- 1 1/2 cups heavy cream
- 1 cup whole milk
- 1 cup grated Parmesan cheese
- 1 tsp dried Italian herbs (or a mix of dried basil, oregano, and thyme)
- 1/2 tsp nutmeg (optional, for subtle warmth)
- 1 1/2 cups shredded mozzarella cheese, divided
- 2 tbsp all-purpose flour
Time You’ll Need:
This casserole takes about 15 minutes to prepare and roughly 25 minutes to bake. You’ll spend some time searing the chicken and making the creamy sauce, then pop everything into the oven for a cozy, bubbling finish. Total time: around 40-45 minutes from start to delicious finish.
Step-by-Step Instructions:
1. Prep and Sear the Chicken:
Preheat your oven to 375°F (190°C) and grease a medium casserole dish. Season the chicken chunks with salt and pepper. Heat olive oil in a large skillet over medium-high heat. Sear the chicken pieces about 3-4 minutes each side until they are golden but not fully cooked through. Remove the chicken and set aside.
2. Create the Creamy Spinach Sauce:
In the same skillet, melt butter, then add garlic and onion. Sauté for 3-4 minutes until fragrant and soft. Sprinkle the flour on top and stir well, cooking for 1-2 minutes to remove the raw flour taste. Slowly whisk in heavy cream and milk, stirring to keep the sauce smooth. Let it simmer for 3-5 minutes until it thickens.
3. Combine and Bake:
Mix in Parmesan, Italian herbs, nutmeg if you like, and half the mozzarella cheese. Add the chopped spinach and cook until wilted and mixed well. Return the chicken to the skillet and coat with the creamy spinach sauce. Transfer everything to the casserole dish, spreading evenly. Sprinkle the remaining mozzarella cheese over the top. Bake uncovered for 20-25 minutes until bubbly and golden on top. Let rest for 5 minutes before serving.
Can I Use Frozen Spinach Instead of Fresh?
Yes, you can! Just make sure to thaw it fully and squeeze out any excess moisture before adding it to the sauce. This helps prevent the casserole from becoming watery.
Can I Substitute the Chicken with Another Protein?
Absolutely! Cooked turkey, ham, or even cooked sausage can be great alternatives and work well with the creamy sauce.
How Do I Store Leftovers?
Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave until warmed through.
Can I Make This Casserole Ahead of Time?
Yes! Prepare the casserole fully, then cover and refrigerate before baking. When ready to eat, bake it in a preheated oven until hot and bubbly, adding about 5-10 extra minutes if chilled.
