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 cooked through, breaking up with a spatula, about 5-6 minutes. Remove turkey from skillet and set aside on a plate.
03 - Add remaining olive oil to the same skillet. Sauté chopped onion for 2-3 minutes until softened. 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, stirring occasionally, for 5 minutes to begin softening the potatoes and bloom the spices.
05 - Add chopped spinach and cooked turkey back to the skillet. Mix well and cook until spinach is just wilted, about 1-2 minutes.
06 - Transfer the turkey and vegetable mixture to the prepared baking dish, spreading evenly. Pour chicken broth evenly over the mixture.
07 - Sprinkle shredded mozzarella and grated Parmesan cheese evenly over the top of the casserole.
08 - Cover the baking dish tightly with aluminum foil. Bake for 30 minutes to allow sweet potatoes to steam and tenderize.
09 - Remove foil and bake for an additional 10-15 minutes, until sweet potatoes are fork-tender and cheese is golden brown and bubbly.
10 - Let the casserole rest for 5 minutes before serving to allow flavors to meld and make serving easier.