Baked Chicken And Zucchini Casserole (Gluten-Free)
This casserole brings together tender chicken, lightly caramelized zucchini, and a creamy, cheesy sauce that bakes into golden comfort. It’s familiar and homey, but still light enough for a weeknight. Everything layers neatly in one dish, which means easy prep and even easier cleanup.
If you’re gluten-free, this recipe fits right in with no special ingredients or complicated swaps. It reheats beautifully, so it’s a great make-ahead option for busy days.
Why This Recipe Works
- Layered texture: Thin-sliced zucchini softens without turning mushy, while the chicken stays juicy under the sauce and cheese.
- Naturally gluten-free: No breadcrumbs or flour needed. The sauce thickens with cream, cheese, and reduced juices.
- Balanced flavors: Garlic, Italian herbs, and a hint of lemon keep it bright.
Parmesan and mozzarella add that craveable pull and savoriness.
- Simple technique: Quick pre-cook for the chicken and a brief sauté for zucchini bring out flavor and prevent watery results.
- Great for meal prep: Holds up well in the fridge, and slices neatly after resting.
Shopping List
- Chicken: 1.5 pounds boneless, skinless chicken breasts (or thighs)
- Zucchini: 3 medium, thinly sliced
- Onion: 1 small yellow onion, thinly sliced
- Garlic: 3–4 cloves, minced
- Cheese: 1 cup shredded mozzarella, 1/2 cup grated Parmesan
- Dairy: 3/4 cup heavy cream (or full-fat coconut milk for dairy-light version)
- Tomatoes (optional but great): 1 cup crushed tomatoes or passata
- Olive oil: 2–3 tablespoons
- Herbs & spices: 1.5 teaspoons Italian seasoning, 1/2 teaspoon crushed red pepper (optional)
- Lemon: Zest of 1/2 lemon + 1 tablespoon juice
- Fresh basil or parsley: A small handful, chopped (for finishing)
- Salt & pepper: To taste
How To Make Baked Chicken And Zucchini Casserole
- Prep the oven and pan: Heat oven to 400°F (200°C). Lightly oil a 9×13-inch baking dish or similar casserole.
- Slice the veg: Cut zucchini into thin rounds (about 1/8–1/4 inch). Slice the onion thinly.
Mince the garlic.
- Season the chicken: Pat dry and slice breasts horizontally into cutlets for even cooking. Season both sides with salt, pepper, and half the Italian seasoning.
- Sear the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Sear chicken 2–3 minutes per side until lightly golden but not fully cooked.
Transfer to a plate.
- Soften the zucchini: Add another tablespoon of oil. Sauté zucchini in batches with a pinch of salt, 2–3 minutes per side, just to drive off moisture and get a little color. Remove to a tray.
- Cook the onions and garlic: Add the remaining oil if needed.
Sauté onion over medium heat for 3–4 minutes until translucent. Stir in garlic for 30 seconds.
- Make a quick sauce: Add crushed tomatoes (if using), cream, remaining Italian seasoning, crushed red pepper, lemon zest, and a pinch of salt and pepper. Simmer 2–3 minutes until slightly thickened.
Taste and adjust seasoning.
- Layer the casserole: Spoon a thin layer of sauce into the baking dish. Add a layer of zucchini, a scatter of onions, and a sprinkle of Parmesan. Place chicken cutlets on top, then spoon more sauce over them.
Finish with remaining zucchini, sauce, mozzarella, and the rest of the Parmesan.
- Bake: Cover loosely with foil and bake 15 minutes. Remove foil and bake another 10–15 minutes until the top is golden and the chicken reaches 165°F (74°C).
- Rest and garnish: Let it sit 10 minutes so it sets. Finish with lemon juice and chopped basil or parsley.
- Serve: Slice into squares.
Pair with a simple green salad or steamed green beans.
Storage Instructions
- Refrigerate: Cool completely, then store in an airtight container for up to 4 days.
- Freeze: Portion into freezer-safe containers. Freeze up to 2 months. Thaw overnight in the fridge.
- Reheat: Oven at 350°F (175°C) for 15–20 minutes until hot.
Microwave individual portions in 60–90 second bursts, resting between to avoid overcooking.
- Meal prep tip: Bake in two smaller dishes—eat one now, freeze one for later.
Health Benefits
- High in protein: Chicken provides sustained energy and supports muscle repair.
- Veg-forward: Zucchini is low in calories and offers potassium, vitamin C, and fiber for digestion and heart health.
- Gluten-free by design: No flour or breadcrumbs, so it’s easier on sensitive stomachs.
- Balanced fats: Olive oil and moderate dairy create a filling meal without heavy starches.
- Lower-carb option: Great if you’re aiming to reduce refined carbs without sacrificing comfort.
Common Mistakes to Avoid
- Skipping the zucchini sauté: Raw zucchini releases water as it bakes, which can make the casserole soupy.
- Overcooking the chicken in the pan: It will finish in the oven. A quick sear is enough.
- Too much sauce: A light coating between layers is best. Excess liquid prevents a set slice.
- Not resting after baking: Give it 10 minutes to settle so the layers slice neatly.
- Underseasoning: Zucchini is mild.
Taste your sauce and season each layer lightly with salt and pepper.
Alternatives
- Dairy-light version: Use full-fat coconut milk instead of cream and reduce mozzarella by half. Add extra Parmesan for flavor without heaviness.
- Tomato-free: Skip crushed tomatoes. Use extra cream and a splash of chicken broth, plus a teaspoon of Dijon for depth.
- Veg swaps: Replace some zucchini with thin-sliced eggplant or yellow squash.
Pre-salt eggplant slices and pat dry to reduce bitterness and moisture.
- Herb variations: Try thyme and oregano, or add smoked paprika for warmth. Fresh basil at the end lifts everything.
- Cheese options: Fontina or provolone melt beautifully. For sharper flavor, add pecorino Romano in place of some Parmesan.
- Protein twist: Use cooked shredded rotisserie chicken; skip the sear and layer it directly with the sauce.
FAQ’s For Baked Chicken And Zucchini Casserole
How thin should I slice the zucchini?
Aim for 1/8–1/4 inch thick. Thin slices cook evenly and layer well without turning soggy.
Can I make this ahead?
Yes. Assemble up to one day in advance, cover, and refrigerate. Add 5–10 extra minutes to the bake time if starting cold.
Is it spicy?
Only if you add crushed red pepper. It’s easy to skip for a mild version.
What if I don’t have heavy cream?
Use half-and-half and simmer the sauce a bit longer to thicken, or try full-fat coconut milk for a dairy-light option.
How do I prevent a watery casserole?
Briefly sauté the zucchini, don’t overload with sauce, and let the casserole rest after baking. These steps keep the layers set.
Can I use frozen zucchini?
Fresh works best. If using frozen, thaw completely and press out excess moisture with paper towels before layering.
What side dishes go well with this?
A simple arugula salad with lemon vinaigrette, roasted carrots, or garlicky green beans is perfect.
How do I know the chicken is done?
Use an instant-read thermometer. The center should reach 165°F (74°C).
In Conclusion
This Baked Chicken & Zucchini Layered Casserole is the kind of meal that feels special but doesn’t demand much from you. It’s naturally gluten-free, balanced, and full of flavor from simple ingredients. With smart layering and a quick sauté, you get clean slices, golden cheese, and juicy chicken every time.
Keep it in your rotation for cozy weeknights, family dinners, or make-ahead lunches that taste just as good on day two.
Baked Chicken & Zucchini Layered Casserole (Gluten-Free)
Ingredients
- Chicken: 1.5 pounds boneless, skinless chicken breasts (or thighs)
- Zucchini: 3 medium, thinly sliced
- Onion: 1 small yellow onion, thinly sliced
- Garlic: 3–4 cloves, minced
- Cheese: 1 cup shredded mozzarella, 1/2 cup grated Parmesan
- Dairy: 3/4 cup heavy cream (or full-fat coconut milk for dairy-light version)
- Tomatoes (optional but great): 1 cup crushed tomatoes or passata
- Olive oil: 2–3 tablespoons
- Herbs & spices: 1.5 teaspoons Italian seasoning, 1/2 teaspoon crushed red pepper (optional)
- Lemon: Zest of 1/2 lemon + 1 tablespoon juice
- Fresh basil or parsley: A small handful, chopped (for finishing)
- Salt & pepper: To taste
Instructions
- Prep the oven and pan: Heat oven to 400°F (200°C). Lightly oil a 9×13-inch baking dish or similar casserole.
- Slice the veg: Cut zucchini into thin rounds (about 1/8–1/4 inch). Slice the onion thinly. Mince the garlic.
- Season the chicken: Pat dry and slice breasts horizontally into cutlets for even cooking. Season both sides with salt, pepper, and half the Italian seasoning.
- Sear the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Sear chicken 2–3 minutes per side until lightly golden but not fully cooked. Transfer to a plate.
- Soften the zucchini: Add another tablespoon of oil. Sauté zucchini in batches with a pinch of salt, 2–3 minutes per side, just to drive off moisture and get a little color. Remove to a tray.
- Cook the onions and garlic: Add the remaining oil if needed. Sauté onion over medium heat for 3–4 minutes until translucent. Stir in garlic for 30 seconds.
- Make a quick sauce: Add crushed tomatoes (if using), cream, remaining Italian seasoning, crushed red pepper, lemon zest, and a pinch of salt and pepper. Simmer 2–3 minutes until slightly thickened. Taste and adjust seasoning.
- Layer the casserole: Spoon a thin layer of sauce into the baking dish. Add a layer of zucchini, a scatter of onions, and a sprinkle of Parmesan. Place chicken cutlets on top, then spoon more sauce over them. Finish with remaining zucchini, sauce, mozzarella, and the rest of the Parmesan.
- Bake: Cover loosely with foil and bake 15 minutes. Remove foil and bake another 10–15 minutes until the top is golden and the chicken reaches 165°F (74°C).
- Rest and garnish: Let it sit 10 minutes so it sets. Finish with lemon juice and chopped basil or parsley.
- Serve: Slice into squares. Pair with a simple green salad or steamed green beans.
