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. Season chicken pieces with salt, pepper, and smoked paprika. Sauté for 4-5 minutes until lightly golden but not fully cooked through. Transfer to a plate and set aside.
03 - Add remaining olive oil to the same skillet. Sauté sliced onion for 2 minutes until translucent. Add minced garlic and cook for 30 seconds until fragrant.
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 retains some crunch.
05 - Stir in baby spinach and cook for 1-2 minutes until just wilted. Remove skillet from heat.
06 - In a mixing bowl, combine heavy cream, dried oregano, dried basil, chili flakes (if using), half the crumbled feta, and half the grated mozzarella. Season with salt and pepper to taste. Whisk until well blended.
07 - Arrange the 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, remaining mozzarella, 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 flavors to meld. Garnish with fresh basil leaves before serving warm.