01 - Preheat oven to 400°F. Lightly grease a 9x13-inch baking dish with cooking spray or a small amount of oil.
02 - Heat 1 tablespoon olive oil in a large skillet over medium heat. Add ground turkey and cook until browned and fully cooked through, breaking up with a spatula as it cooks, approximately 5-6 minutes. Transfer turkey to a plate and set aside.
03 - Add remaining olive oil to the same skillet. Sauté chopped onion for 2-3 minutes until softened and translucent. Add minced garlic and diced red bell pepper, cooking for another 2 minutes until fragrant.
04 - Stir in diced sweet potatoes, dried thyme, oregano, smoked paprika, salt, and black pepper. Cook mixture, stirring occasionally to prevent sticking, for about 5 minutes to begin softening the potatoes.
05 - Add chopped spinach and cooked turkey back into the skillet. Mix thoroughly to distribute all ingredients evenly. Cook just until spinach begins to wilt, about 1-2 minutes.
06 - Transfer the entire mixture to the prepared baking dish, spreading it evenly. Pour chicken broth over the top in a circular motion to distribute moisture throughout the dish.
07 - Sprinkle shredded mozzarella and grated Parmesan cheese evenly across the top of the casserole, covering the surface completely.
08 - Cover baking dish tightly with aluminum foil. Bake for 30 minutes to allow sweet potatoes to steam and soften.
09 - Remove foil and return to oven for an additional 10-15 minutes, or until sweet potatoes are tender when pierced with a fork and cheese is melted and golden brown.
10 - Let casserole rest for 5 minutes before serving to allow flavors to meld and make serving easier.