1. Preheat the Oven
Start by preheating your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish or a similar ovenproof dish.
2. Sauté the Vegetables
In a skillet, heat the olive oil over medium heat. Add the garlic and sliced mushrooms and sauté for 3–4 minutes until the mushrooms are tender and fragrant. Stir in the chopped spinach and cook until just wilted. This ensures the vegetables retain their flavor and don’t release too much moisture into the bake.
3. Prepare the Creamy Sauce
In a small bowl, mix the cream of mushroom soup and sour cream until smooth. Add Italian seasoning, salt, and pepper to taste. This sauce will keep the chicken juicy and infuse the vegetables with flavor as it bakes.
4. Assemble the Bake
Place the chicken breasts in the prepared baking dish. Spread the sautéed mushroom and spinach mixture evenly over the chicken. Pour the creamy mushroom sauce over the top, making sure the chicken is fully coated.
5. Add Cheese and Bake
Sprinkle shredded mozzarella cheese over the top of the casserole. Bake uncovered for 25–30 minutes, or until the chicken is cooked through and the cheese is bubbly and golden. For an extra crispy top, broil for 2–3 minutes at the end.
6. Serve and Enjoy
Remove the casserole from the oven and let it rest for 5 minutes before serving. This helps the sauce set slightly and makes it easier to serve.
Cooking Tips for Maximum Flavor
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Sear the chicken in a hot skillet for 2–3 minutes per side before baking for extra flavor and golden color.
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Add extra vegetables like bell peppers, zucchini, or cherry tomatoes for a colorful twist.
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Use a blend of mozzarella and Parmesan cheese for a richer, more complex flavor.
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If you prefer a lighter version, substitute Greek yogurt for the sour cream.
Serving Suggestions