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 with salt, pepper, and smoked paprika. Sauté for 4–5 minutes until lightly golden but not cooked through. Transfer to a plate.
03 - Add remaining olive oil to the same skillet. Sauté onion for 2 minutes until softened, then add garlic and cook until fragrant, about 30 seconds.
04 - Add zucchini and sun-dried tomatoes to the skillet. Cook for 3–4 minutes, stirring occasionally, until zucchini just starts to soften.
05 - Stir in baby spinach and cook until just wilted. Remove from heat.
06 - In a 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 chicken pieces in the prepared baking dish. Pour cream mixture evenly over the top.
08 - Sprinkle with remaining feta cheese, remaining mozzarella cheese, and all the Parmesan cheese.
09 - Bake for 25–30 minutes until chicken is cooked through and the top is golden and bubbly.
10 - Let rest for 5 minutes before garnishing with fresh basil leaves and serving.