Chicken and Spinach Casserole

Chicken and Spinach Casserole is one of those recipes that feels like a warm hug on a plate. It’s packed with tender pieces of chicken, fresh spinach, and a creamy…

By Riley • February 28, 2026 • Reading time: 6 min

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Chicken and Spinach Casserole is one of those recipes that feels like a warm hug on a plate. It’s packed with tender pieces of chicken, fresh spinach, and a creamy sauce, all baked together until golden and bubbly. The mix of flavors and textures makes it really satisfying without being complicated.

I love making this casserole because it’s super simple but still feels special enough for a cozy dinner. The spinach adds a nice fresh touch that balances the richness of the creamy sauce and melted cheese. One of my favorite tricks is to toss in a little garlic and onion for extra flavor—it makes the whole dish smell amazing while it cooks.

This casserole works great for leftovers too, and I often slice it up for easy lunches the next day. I like serving it with a simple side salad or some crusty bread to soak up all the tasty sauce. It’s the kind of meal that brings everyone together and always leaves you feeling full and happy.

Key Ingredients & Substitutions

Chicken breasts: They’re great for this casserole because they cook evenly and stay tender. You could use chicken thighs if you prefer juicier meat.

Spinach: Fresh spinach adds a nice texture, but frozen works well too. Just be sure to drain frozen spinach well to avoid excess water in the dish.

Cream cheese and sour cream: These give a creamy base. Greek yogurt is a healthier swap for sour cream and adds a slight tang.

Mozzarella and Parmesan cheese: Mozzarella melts beautifully and gives stretch, while Parmesan adds flavor depth. You can swap mozzarella for cheddar or provolone if you like.

Mushrooms, onion, and garlic: These boost flavor and texture. Don’t skip sautéing them first—it makes a big difference.

How Do You Get the Creamy, Flavorful Filling Just Right?

The secret is in preparing the veggies and mixing the creamy base well before baking.

• Sauté onion and garlic until soft to release their aroma and sweetness (about 3-4 minutes).
• Add mushrooms and cook until they shrink and soften, which takes about 5 minutes, so no watery bites.
• If using fresh spinach, add it last and cook until just wilted—overcooking makes it soggy. If frozen, drain well before mixing.
• Mix the softened cream cheese and sour cream (or Greek yogurt) until smooth before combining with veggies. This keeps the filling creamy without lumps.
• Season the mixture with dried herbs, salt, and pepper for balanced flavor.

Following these steps sets the stage for a rich, tasty casserole with well-blended flavors and creamy texture.

Equipment You’ll Need

• Large skillet – perfect for sautéing onions, garlic, and mushrooms evenly without crowding.
• Mixing bowl – helps you blend the cream cheese and sour cream smoothly with veggies.
• Casserole dish (around 9×13 inches) – roomy enough to hold the chicken and creamy topping without spilling.
• Knife and cutting board – for chopping spinach, onion, and mushrooms with ease.
• Meat thermometer – ensures your chicken is cooked safely to 165°F for juicy results.

Flavor Variations & Add-Ins

• Swap chicken breasts for turkey breasts when you want a slightly leaner protein.
• Add cooked bacon bits for a smoky crunch that pairs well with creamy spinach.
• Mix in sun-dried tomatoes to add a tangy sweet burst that brightens the casserole.
• Try shredded cheddar or pepper jack cheese instead of mozzarella for a sharper or spicier flavor.

Chicken and Spinach Casserole

Ingredients You’ll Need:

Main Ingredients:

• 4 boneless, skinless chicken breasts
• 2 cups fresh spinach leaves (or 1 cup frozen spinach, thawed and drained)
• 1 cup mushrooms, sliced
• 1 cup cream cheese, softened
• 1 cup sour cream or Greek yogurt
• 1 cup shredded mozzarella cheese
• 1/2 cup grated Parmesan cheese
• 2 cloves garlic, minced
• 1 small onion, finely chopped
• 1 tbsp olive oil or butter
• 1/2 tsp dried thyme
• 1/2 tsp dried oregano
• Salt and pepper to taste
• Fresh parsley, chopped (for garnish)

How Much Time Will You Need?

This dish takes about 15 minutes to prepare and 30-35 minutes to bake. Plan for a total of around 45 minutes from start to finish, including a short rest after baking to let it set for the best flavor.

Step-by-Step Instructions:

1. Preheat and Sauté the Veggies:

Start by preheating your oven to 375°F (190°C). Heat olive oil or butter in a skillet on medium. Add the onion and garlic, cooking for about 3-4 minutes until they smell great and look clear. Then add the mushrooms and cook for around 5 minutes until soft and tender.

2. Cook the Spinach and Mix the Filling:

Add the spinach to the skillet. If fresh, cook just until it wilts; if frozen, make sure to drain it well before adding. Remove the skillet from heat. In a bowl, mix the softened cream cheese with the sour cream or Greek yogurt until smooth. Stir in the cooked vegetables, thyme, oregano, salt, and pepper until everything is combined nicely.

3. Assemble and Bake:

Season the chicken breasts with salt and pepper. Place them in a greased casserole dish, then pour the creamy vegetable mixture evenly over the chicken. Sprinkle shredded mozzarella and grated Parmesan evenly on top. Bake in the oven for 30-35 minutes, until the chicken is cooked through (internal temp 165°F or 75°C) and the cheese is bubbly and golden.

4. Rest and Serve:

Once baked, take the casserole out of the oven and let it rest for 5 minutes. This lets the flavors set and makes it easier to serve. Garnish with fresh chopped parsley before bringing it to the table. Enjoy your creamy, cheesy chicken and spinach casserole!

Can I Use Frozen Spinach Instead of Fresh?

Yes! Just make sure to thaw it completely and squeeze out as much moisture as possible before adding. This helps prevent your casserole from becoming watery.

Can I Substitute Greek Yogurt for Sour Cream?

Absolutely! Greek yogurt works well as a healthier substitute and adds a nice tangy flavor. Use it in the same amount as sour cream in the recipe.

How Do I Store Leftovers?

Keep leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the microwave or oven until warmed through.

Can I Make This Recipe Ahead of Time?

Yes, you can assemble the casserole up to a day in advance and keep it covered in the fridge. When ready, bake as directed, adding a few extra minutes if baking straight from cold.