01 - Preheat the oven to 400°F. Lightly grease a 9x13-inch baking dish and set aside.
02 - Heat olive oil in a large skillet over medium heat. Add the diced onion, minced garlic, and diced red bell pepper. Cook for 3 to 4 minutes, stirring occasionally, until the vegetables are softened and fragrant.
03 - Add the ground turkey to the skillet along with the ground cumin, paprika, chili powder, dried oregano, salt, and black pepper. Cook for 5 to 6 minutes, breaking the meat apart with a spoon, until the turkey is fully browned and no longer pink.
04 - Stir in the drained black beans and drained diced tomatoes. Let the mixture simmer together for about 3 minutes to meld the flavors, then remove from heat.
05 - Spread half of the diced sweet potatoes in an even layer across the bottom of the prepared baking dish. Spoon half of the turkey and black bean mixture over the sweet potatoes, spreading it out evenly.
06 - Repeat the layering with the remaining sweet potatoes followed by the rest of the turkey and black bean mixture, distributing everything uniformly across the dish.
07 - Cover the baking dish tightly with aluminum foil and place it in the preheated oven. Bake for 25 to 30 minutes until the sweet potatoes are just becoming tender when pierced with a fork.
08 - Remove the foil and sprinkle the shredded Monterey Jack or cheddar cheese evenly over the top. Return the dish to the oven uncovered and bake for an additional 10 minutes until the cheese is fully melted and bubbling.
09 - Remove the bake from the oven and let it rest for 5 to 10 minutes so the layers set. Garnish with fresh chopped cilantro and serve with a dollop of sour cream if desired.