Step 1: Prepare the Sloppy Joe Filling

1. Heat the olive oil in a large skillet over medium heat. Add the diced onion and bell pepper, and sauté for 3-4 minutes, until softened.
2. Add the minced garlic and cook for an additional 30 seconds, until fragrant.
3. Push the vegetables to one side of the skillet and add the ground turkey. Cook for 5-6 minutes, breaking it apart with a spatula, until browned and cooked through.
4. Stir in the tomato sauce, ketchup, tomato paste, Worcestershire sauce, Dijon mustard, brown sugar, smoked paprika, and chili powder. Simmer the mixture for 5-7 minutes, stirring occasionally, until thickened. Season with salt and pepper to taste. Remove from heat and set aside.

Step 2: Prepare the Base

For Cornbread Base:

1. Preheat your oven to 375°F.
2. In a mixing bowl, prepare the cornbread batter according to the package instructions, combining the mix with milk and an egg.
3. Pour the batter into a greased 9×13-inch baking dish, spreading it evenly to form the base layer.

For Bun Base:

1. Arrange the toasted bun halves in a single layer at the bottom of a greased 9×13-inch baking dish, cutting or overlapping them slightly if needed to cover the surface.

Step 3: Assemble the Casserole

1. Spoon the prepared sloppy joe filling evenly over the cornbread batter or buns, spreading it to cover the base layer completely.
2. Sprinkle the shredded cheddar cheese over the filling, ensuring an even distribution.

Step 4: Bake the Casserole

1. Place the casserole in the preheated oven and bake for 25-30 minutes, or until the cheese is melted and bubbly. If using a cornbread base, ensure the cornbread is fully set by inserting a toothpick into the center—it should come out clean.
2. Remove from the oven and let the casserole rest for 5 minutes before serving.

Step 5: Garnish and Serve

1. Sprinkle the casserole with chopped parsley or green onions for a fresh, vibrant touch.
2. Slice into portions and serve warm. Pair with a crisp green salad or steamed vegetables for a complete meal.