Creamy Spinach Chicken Casserole (Low Carb, 47g Protein)

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases at no extra cost to you.

Jump to Recipe

This creamy spinach chicken casserole is one of those low-effort dinners that tastes like you worked much harder than you did. Juicy chicken breasts are baked on a bed of fresh spinach, smothered in a tangy Parmesan cream sauce, and finished with a bubbly blanket of melted Monterey Jack. It takes about 10 minutes to put together, it’s naturally low carb, and each serving packs around 47 grams of protein.

It’s a lighter take on the classic mayo-and-sour-cream chicken bake. I use Greek yogurt for most of the creaminess and just a little mayonnaise for richness, so it’s still indulgent but not heavy.

Why You’ll Love This Casserole

• Ten minutes of prep. No pre-cooking. Just layer, spread and bake.
• Low carb and keto friendly. About 3 grams of net carbs per serving.
• High protein. Chicken, Greek yogurt and two cheeses make it filling and satisfying.
• Sneaks in greens. A whole bag of spinach melts into the sauce. Even picky eaters barely notice.
• Juicy every time. The sauce protects the chicken, so it stays moist in the oven.

Ingredients For Spinach Chicken Casserole

You’ll only need a handful of ingredients. See the recipe card below for exact amounts.

For the casserole

• Chicken breasts: about 2 pounds, boneless and skinless. Slice each breast in half horizontally into thinner cutlets so they cook quickly and evenly.
• Fresh baby spinach: an 8-ounce bag or container. It looks like a lot, but it wilts down dramatically.
• Monterey Jack cheese: 1½ cups, shredded, for a mild, melty top. Mozzarella or pepper jack are great swaps.

For the creamy Parmesan sauce

• Plain Greek yogurt: ½ cup of whole or 2%. It adds protein and tang.
• Mayonnaise: ¼ cup for richness and to keep the sauce silky in the oven.
• Parmesan cheese: ½ cup, finely grated, for salty, nutty flavor.
• Garlic salt and black pepper: simple seasoning that pairs perfectly with chicken and spinach.
• Italian seasoning: optional, but a teaspoon adds a lovely herby note.

Equipment

• A 9×13-inch baking dish
• A sharp chef’s knife for slicing the chicken into cutlets
• A mixing bowl and spatula
• An instant-read thermometer

How to Make Creamy Spinach Chicken Casserole

Step 1: Preheat and prep the dish

Preheat the oven to 400°F (200°C). Lightly grease a 9×13-inch baking dish with olive oil or cooking spray.

Step 2: Make the sauce

In a mixing bowl, stir together the Greek yogurt, mayonnaise, Parmesan, garlic salt, pepper and Italian seasoning until smooth and creamy.

Step 3: Layer the spinach and chicken

Spread the fresh spinach evenly over the bottom of the baking dish. Slice the chicken breasts in half horizontally to make thinner cutlets, pat them dry, and lay them over the spinach in a single layer.

Step 4: Spread the sauce and add cheese

Spoon the creamy sauce over the chicken and spread it evenly so each piece is covered. Sprinkle the shredded Monterey Jack over the top.

Step 5: Bake

Bake uncovered for 25 to 30 minutes, until the chicken reaches 165°F in the center and the cheese is melted and golden in spots. For extra browning, broil for 2 minutes at the end.

Step 6: Rest and serve

Let the casserole rest for 5 minutes. The spinach will have released some liquid that mingles with the sauce, making a creamy, savory base to spoon over the chicken.

Tips for the Best Results

• Pound or slice the chicken thin. Thinner cutlets cook in the same time the cheese browns, so nothing dries out.
• Pat the chicken dry. Removing surface moisture keeps the sauce from getting watery.
• Use fresh spinach. If you use frozen, thaw it and squeeze out every drop of water first.
• Use a thermometer. Chicken breast goes from juicy to dry quickly. Pull it at 165°F.
• Grate your own cheese. Freshly shredded Monterey Jack and Parmesan melt far better than bagged.

Troubleshooting

The sauce is watery. Spinach and chicken both release liquid. Pat the chicken dry, don’t use more spinach than the recipe calls for, and let the dish rest before serving.

The chicken is dry. The cutlets may have been very thin or baked too long. Check the temperature a few minutes early next time.

The sauce separated. Nonfat yogurt can break in high heat. Use whole or 2% Greek yogurt, and keep the mayonnaise in the recipe for stability.

Variations

• Spinach and artichoke: add a drained, chopped can of artichoke hearts with the spinach. For a stovetop version, see my creamy spinach artichoke chicken.
• Sun-dried tomato: scatter ⅓ cup of chopped sun-dried tomatoes over the chicken before adding the sauce.
• Spicy: use pepper jack cheese and add a pinch of red pepper flakes to the sauce.
• Mushroom: add a layer of sliced mushrooms on top of the spinach.
• Classic version: use ½ cup of mayonnaise and ½ cup of sour cream instead of the yogurt and mayo for the original, richer style.

If you like cheesy chicken bakes, try my caprese chicken casserole or the tangy creamy pepperoncini chicken next.

What to Serve With It

For a low-carb meal, serve it with cauliflower rice, roasted broccoli, zucchini noodles or a simple side salad. If carbs aren’t a concern, it’s excellent over rice, egg noodles or mashed potatoes, which soak up the creamy sauce. Crusty bread for mopping up the plate is never a bad idea.

Storage and Reheating

How long do leftovers keep?

Store leftovers in an airtight container in the fridge for up to 3 to 4 days.

How should I reheat it?

Reheat individual portions in the microwave at 50% power, or warm the whole dish covered with foil in a 325°F oven until heated through. Gentle heat keeps the chicken from drying out and the sauce from separating.

Can I freeze it?

You can, but dairy sauces can turn slightly grainy after freezing. For the best texture, freeze for no more than 2 months and reheat slowly.

Is This Casserole Healthy?

This is a well-balanced, protein-forward dinner. Each serving has about 400 calories, 47 grams of protein and only 3 grams of carbohydrates, which makes it a great fit for low-carb, keto or high-protein eating plans. The spinach adds iron, folate, vitamin K and fiber. Swapping most of the mayonnaise for Greek yogurt cuts fat and adds protein compared with the traditional version. To lighten it even more, use part-skim mozzarella instead of Monterey Jack.

Make It a Meal Prep Favorite

This casserole is ideal for weekly meal prep. Bake it on Sunday, let it cool, then divide the chicken, spinach and sauce into containers with a side of roasted vegetables or cauliflower rice. It keeps well for four days, and the flavors get even better overnight. For variety, slice the leftover chicken and toss it into a salad or tuck it into a low-carb wrap.

Can I Assemble It Ahead of Time?

Yes. Layer the spinach and chicken, spread on the sauce, and add the cheese, then cover tightly and refrigerate for up to 24 hours. When you’re ready to eat, let it sit on the counter while the oven heats, then bake as directed, adding about 5 minutes to the cooking time. This makes it an excellent option for busy weeknights or for bringing a meal to a friend.

Why Spinach and Chicken Work So Well Together

Spinach is mild, slightly earthy and soaks up whatever flavors surround it, which makes it a natural match for chicken and a rich, cheesy sauce. As the casserole bakes, the spinach wilts into a silky layer under the chicken and absorbs the juices that drip down, so none of that flavor goes to waste. The Parmesan and garlic in the sauce then tie everything together, giving the dish the same comforting flavor profile as a creamy spinach dip.

There’s also a practical benefit. Because the spinach sits under the chicken, it acts like a buffer against the hot pan, helping the chicken cook gently and stay juicy instead of drying out on the bottom.

Choosing the Right Chicken

Boneless, skinless chicken breasts are the classic choice, but their size varies a lot. Many grocery store breasts weigh 10 to 12 ounces each, which is too thick to cook evenly in 30 minutes. That’s why I slice them horizontally into cutlets about ¾ inch thick. If you prefer, you can buy pre-cut thin cutlets or chicken tenderloins, which work perfectly here. Just check the temperature a few minutes early, since thinner pieces cook faster.

If you’d like more flavor and extra insurance against dry chicken, boneless thighs are a great option. They’re more forgiving, and their slightly richer flavor pairs beautifully with the creamy Parmesan sauce.

Cheese Options

Monterey Jack is mild and melts beautifully, but you have lots of choices. Mozzarella gives a stretchy, pizza-like top. Pepper jack adds a little heat. Sharp white cheddar brings bolder flavor, and a mix of Gruyère and Parmesan makes it feel a little fancy. Whatever you choose, aim for about 1½ cups of freshly shredded cheese.

Frequently Asked Questions

Can I use frozen spinach?

Yes. Use a 10-ounce package, thawed and squeezed very dry in a clean towel. Spread it evenly in the dish before adding the chicken.

Can I use chicken thighs?

Absolutely. Boneless, skinless thighs stay very juicy. Bake them for 30 to 35 minutes, until they reach 175°F for the most tender texture.

Can I skip the mayonnaise?

You can use all Greek yogurt, but the sauce may be a little thinner and more likely to separate. A small amount of mayo keeps it stable and creamy.

Is this recipe gluten free?

Yes, as long as your garlic salt and Italian seasoning are gluten free, which most are.

How many carbs are in a serving?

About 3 grams of carbohydrates and 1 gram of fiber per serving, based on six servings.

Creamy, Cheesy and Easy

With juicy chicken, tender spinach and a tangy Parmesan sauce under melted cheese, this casserole is a weeknight dinner you’ll come back to again and again. Give it a try, then leave a star rating and a comment below. Don’t forget to pin it to your low-carb dinners board.

Nutrient	Amount
Calories	400 kcal
Protein	47 g
Carbohydrates	3 g
Fat	22 g
Saturated Fat	9 g
Fiber	1 g
Sugar	1 g
Sodium	660 mg

Nutrition values are estimates calculated from standard ingredient data and will vary with the brands and exact amounts you use.