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 partially cooked chicken to a plate and set aside.
03 - In the same skillet, add remaining olive oil. Sauté sliced red onion for 2 minutes until translucent, 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, 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 incorporated.
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 coats the chicken and vegetables evenly.
08 - Sprinkle the 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 fully cooked through (internal temperature reaches 165°F) and the cheese topping is golden brown and bubbly.
10 - Remove from oven and let the dish rest for 5 minutes to allow flavors to meld. Garnish with fresh basil leaves before serving warm.