01 - Preheat oven to 400°F. Lightly grease a medium baking dish with cooking spray or a small amount of olive oil.
02 - Heat 1 tbsp olive oil in a large skillet over medium-high heat. Season chicken pieces with salt, pepper, and smoked paprika. Sauté for 4–5 minutes until lightly golden on all sides but not cooked through. Transfer to a plate and set aside.
03 - In the same skillet, add remaining olive oil. Sauté sliced onion for 2 minutes until softened, then add minced garlic and cook until fragrant, about 30 seconds.
04 - Add zucchini slices and chopped sun-dried tomatoes to the skillet. Cook for 3–4 minutes until zucchini begins to soften but still retains some crunch.
05 - Stir in baby spinach and cook until just wilted, about 1 minute. Remove skillet from heat.
06 - In a mixing bowl, combine heavy cream, dried oregano, dried basil, chili flakes (if using), half the feta cheese, and half the mozzarella cheese. Season with salt and pepper to taste.
07 - Arrange sautéed vegetables and seared chicken pieces in the prepared baking dish. Pour the cream mixture evenly over the top, ensuring all ingredients are coated.
08 - Sprinkle the remaining feta cheese, remaining mozzarella cheese, and all the Parmesan cheese over the top of the dish.
09 - Bake for 25–30 minutes until chicken is cooked through (internal temperature reaches 165°F) and the cheese topping is golden brown and bubbling.
10 - Let the dish rest for 5 minutes to allow the sauce to thicken slightly. Garnish with fresh basil leaves and serve warm.