01 - Preheat oven to 400°F. Lightly grease a medium baking dish with olive oil or cooking spray.
02 - Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add chicken pieces, season generously 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. Add sliced onion and sauté for 2 minutes until softened. Add minced garlic and cook until fragrant, about 30 seconds, being careful not to burn.
04 - Add zucchini slices and chopped sun-dried tomatoes to the skillet. Cook for 3–4 minutes, stirring occasionally, until zucchini begins to soften but still holds its shape.
05 - Stir in baby spinach and cook for 1–2 minutes until just wilted. Remove skillet from heat.
06 - In a medium bowl, whisk together heavy cream, dried oregano, dried basil, chili flakes (if using), half the crumbled feta, and half the mozzarella. Season with salt and pepper to taste.
07 - Transfer sautéed vegetables to the prepared baking dish. Arrange seared chicken pieces evenly over the vegetables. Pour the cream mixture over the top, ensuring it distributes evenly.
08 - Sprinkle remaining feta, remaining mozzarella, and all the Parmesan cheese evenly over the top of the dish.
09 - Bake for 25–30 minutes until chicken is cooked through (internal temperature reaches 165°F), sauce is bubbling, and cheese topping is golden brown.
10 - Remove from oven and let rest for 5 minutes to allow flavors to settle. Garnish with fresh basil leaves and serve warm.