Zucchini Chicken Casserole With Mozzarella – A Cozy, Cheesy Weeknight Favorite

This casserole brings together tender chicken, fresh zucchini, and melty mozzarella in a creamy, comforting bake. It’s simple to put together, uses everyday ingredients, and tastes like something you’d get at a cozy neighborhood bistro. The flavors are bright and savory, with just enough creaminess to feel indulgent without being heavy.

If you’re looking for a dependable dinner that works for family nights, meal prep, or guests, this one checks every box.

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Zucchini Chicken Casserole With Mozzarella - A Cozy, Cheesy Weeknight Favorite

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Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 50 minutes mins

Servings 6 servings

Ingredients

  

• 2 medium zucchinis, thinly sliced into half-moons
• 1 1/2 pounds boneless, skinless chicken breasts, cut into bite-size pieces
• 1 small yellow onion, finely diced
• 3 cloves garlic, minced
• 1 cup marinara sauce (or tomato basil sauce)
• 1/2 cup chicken broth
• 1/2 cup heavy cream (or half-and-half for lighter)
• 1 1/2 cups shredded mozzarella cheese, divided
• 1/4 cup grated Parmesan cheese
• 2 tablespoons olive oil
• 1 teaspoon Italian seasoning
• 1/2 teaspoon crushed red pepper flakes (optional)
• Salt and black pepper, to taste
• Fresh basil or parsley, chopped, for garnish
• Nonstick cooking spray or extra oil for the baking dish

Instructions

 

• Prep the oven and dish: Preheat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with cooking spray or olive oil.
• Season the chicken: Pat the chicken dry. Season with 1/2 teaspoon salt, 1/4 teaspoon black pepper, and half of the Italian seasoning.
• Sauté the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Add chicken and cook 4–6 minutes until lightly browned and just cooked through. Transfer to a plate.
• Cook the aromatics: In the same skillet, add the remaining 1 tablespoon olive oil. Sauté the onion for 3–4 minutes until soft. Add garlic and cook 30 seconds until fragrant.
• Build the sauce: Lower heat to medium. Stir in marinara, chicken broth, heavy cream, remaining Italian seasoning, and red pepper flakes. Simmer 2–3 minutes, then season to taste with salt and pepper.
• Par-cook the zucchini: Add the zucchini to the skillet and toss to coat. Cook 2–3 minutes, just until slightly tender but still crisp. Don’t overcook—they’ll bake further.
• Combine: Return the chicken to the skillet and fold in 1/2 cup shredded mozzarella and the Parmesan until just mixed.
• Assemble the casserole: Pour everything into the prepared baking dish and spread evenly. Top with the remaining 1 cup mozzarella.
• Bake: Bake uncovered for 18–22 minutes, until bubbly and the cheese is melted with golden spots.
• Rest and garnish: Let the casserole rest 5–10 minutes to set. Sprinkle with chopped basil or parsley before serving.

What Makes This Recipe So Good

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• Balanced and satisfying: Lean chicken and zucchini keep it light, while mozzarella and a creamy sauce add richness.
• Simple prep: No tricky techniques. Basic sautéing, layering, and baking do the job.
• Weeknight-friendly: Uses one skillet and a baking dish, and it reheats beautifully.
• Kid-approved flavors: Mild, cheesy, and comforting, with room for a little spice if you like.
• Flexible: Swap in different veggies, sauces, or cheeses without changing the spirit of the dish.

What You’ll Need

• 2 medium zucchinis, thinly sliced into half-moons
• 1 1/2 pounds boneless, skinless chicken breasts, cut into bite-size pieces
• 1 small yellow onion, finely diced
• 3 cloves garlic, minced
• 1 cup marinara sauce (or tomato basil sauce)
• 1/2 cup chicken broth
• 1/2 cup heavy cream (or half-and-half for lighter)
• 1 1/2 cups shredded mozzarella cheese, divided
• 1/4 cup grated Parmesan cheese
• 2 tablespoons olive oil
• 1 teaspoon Italian seasoning
• 1/2 teaspoon crushed red pepper flakes (optional)
• Salt and black pepper, to taste
• Fresh basil or parsley, chopped, for garnish
• Nonstick cooking spray or extra oil for the baking dish

Step-by-Step Instructions

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1. Prep the oven and dish: Preheat the oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with cooking spray or olive oil.
2. Season the chicken: Pat the chicken dry.

   Season with 1/2 teaspoon salt, 1/4 teaspoon black pepper, and half of the Italian seasoning.

3. Sauté the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Add chicken and cook 4–6 minutes until lightly browned and just cooked through. Transfer to a plate.
4. Cook the aromatics: In the same skillet, add the remaining 1 tablespoon olive oil.

   Sauté the onion for 3–4 minutes until soft. Add garlic and cook 30 seconds until fragrant.

5. Build the sauce: Lower heat to medium. Stir in marinara, chicken broth, heavy cream, remaining Italian seasoning, and red pepper flakes.

   Simmer 2–3 minutes, then season to taste with salt and pepper.

6. Par-cook the zucchini: Add the zucchini to the skillet and toss to coat. Cook 2–3 minutes, just until slightly tender but still crisp. Don’t overcook—they’ll bake further.
7. Combine: Return the chicken to the skillet and fold in 1/2 cup shredded mozzarella and the Parmesan until just mixed.
8. Assemble the casserole: Pour everything into the prepared baking dish and spread evenly.

   Top with the remaining 1 cup mozzarella.

9. Bake: Bake uncovered for 18–22 minutes, until bubbly and the cheese is melted with golden spots.
10. Rest and garnish: Let the casserole rest 5–10 minutes to set. Sprinkle with chopped basil or parsley before serving.

How to Store

• Refrigerator: Cool completely, then store in an airtight container for up to 4 days.
• Freezer: Cool, portion into freezer-safe containers, and freeze for up to 2 months. Thaw overnight in the fridge before reheating.
• Reheat: Warm in a 350°F (175°C) oven, covered with foil, for 15–20 minutes.

  For single servings, microwave in 45-second bursts, stirring gently between rounds.

Health Benefits

• Lean protein: Chicken supports muscle repair and keeps you full longer.
• Veggie-forward: Zucchini is low in calories and provides vitamin C, potassium, and fiber.
• Balanced fats: A modest amount of dairy adds calcium and helps with satiety. You can lighten it by using half-and-half or part-skim mozzarella.
• Lower-carb option: This casserole skips pasta and breading, making it friendly for lower-carb eating styles.

What Not to Do

• Don’t overcook the zucchini: Mushy zucchini can water down the sauce. Keep it slightly crisp before baking.
• Don’t skip seasoning: Taste the sauce and adjust salt and pepper.

  Bland sauce leads to a bland casserole.

• Don’t use watery sauce: Thin marinara will make the casserole soupy. Choose a thicker sauce or simmer to reduce.
• Don’t overcrowd the skillet: Cook chicken in batches if needed to get light browning and better flavor.
• Don’t slice zucchini too thick: Aim for about 1/4-inch slices so they cook evenly.

Variations You Can Try

• Herb and lemon twist: Add 1 teaspoon lemon zest and extra basil for brightness.
• Creamy pesto: Swap marinara for 1/2 cup pesto and 1/2 cup cream. Top with cherry tomatoes.
• Spicy arrabbiata: Use a spicy tomato sauce and add extra red pepper flakes or a pinch of chili powder.
• Mushroom medley: Sauté 8 ounces sliced mushrooms with the onions for extra umami.
• Spinach boost: Stir in 2 cups baby spinach right before baking; it wilts perfectly.
• Different cheeses: Mix mozzarella with provolone or fontina for extra melt, or add a little smoked mozzarella.
• Gluten-free topping: Sprinkle with gluten-free pork rind crumbs or almond flour mixed with Parmesan for a browned crust.

FAQ

Can I use rotisserie chicken?

Yes.

Shred about 4 cups of cooked rotisserie chicken and skip the sautéing step for the chicken. Warm it in the sauce before assembling.

How do I prevent a watery casserole?

Use a thick marinara, don’t overcook the zucchini on the stove, and let the casserole rest after baking so the sauce thickens. You can also add an extra 2 tablespoons Parmesan to help bind.

Can I make it ahead?

Absolutely.

Assemble up to the cheese topping, cover, and refrigerate for up to 24 hours. Add 5–10 minutes to the bake time if going straight from the fridge.

What can I serve with it?

A simple green salad, garlic bread, or roasted potatoes all work well. For a lighter side, try steamed green beans or a tomato-cucumber salad.

Is there a dairy-free option?

Use a dairy-free mozzarella-style shreds and swap the cream for full-fat coconut milk or a barista-style oat cream.

The flavor will be slightly different but still delicious.

Can I substitute the zucchini?

Yes. Yellow squash, eggplant (salt and pat dry first), or thinly sliced bell peppers are good options. Adjust cook time to keep them slightly crisp before baking.

What skillet size should I use?

A large 12-inch skillet is ideal to prevent overcrowding.

If your skillet is smaller, cook in batches and combine in the baking dish.

Wrapping Up

This Zucchini Chicken Casserole with Mozzarella is the kind of meal that makes weeknights easier and more delicious. It’s simple, flexible, and full of satisfying flavors, with just enough cheese to make it special. Keep the basic method, tweak the flavors to your taste, and you’ll have a reliable go-to that never gets boring.

Enjoy it fresh from the oven, and save the leftovers for a win the next day.