Step 1: Prepare Your Pan and Preheat the Oven

Preheat your oven to 400°F (200°C). Ensure you are using a large, deep, oven-safe skillet (a 12-inch cast-iron skillet is ideal) or a 9×13-inch baking dish. If using a separate baking dish, you’ll cook the filling in a skillet first and then transfer it.

Step 2: Brown the Ground Beef and Vegetables

Place your oven-safe skillet over medium-high heat and add the olive oil. Once shimmering, add the diced yellow onion and green bell pepper. Sauté for 4-5 minutes until they begin to soften. Add the ground beef to the skillet. Break it apart with a wooden spoon or spatula and cook until it is browned all over, about 7-8 minutes. Once the beef is cooked, drain off any excess grease from the pan, leaving about a tablespoon for flavor.

Step 3: Bloom the Spices and Aromatics

Return the skillet to medium heat. Add the minced garlic and cook for about 1 minute until fragrant, being careful not to let it burn. Add the chili powder, smoked paprika, cumin, and dried oregano directly to the pan. Stir constantly for about 30 seconds. This step, known as “blooming,” toasts the spices and unlocks their full aromatic potential, adding incredible depth to the casserole.

Step 4: Create the Rich Filling

Pour in the tomato sauce, the undrained can of diced tomatoes with green chiles, tomato paste, and Worcestershire sauce. Stir everything together until well combined. Bring the mixture to a gentle simmer.

Step 5: Add the Beans and Corn

Fold in the rinsed kidney beans, pinto beans, and drained corn. Stir gently to incorporate them into the beef mixture. Season with salt and black pepper. Allow the filling to simmer for 5-10 minutes, stirring occasionally. This allows the flavors to meld together and the sauce to thicken slightly. Taste and adjust seasoning if necessary.

Step 6: Prepare the Cornbread Topping

While the filling simmers, prepare the cornbread batter in a separate medium bowl.

• Combine Dry Ingredients: Whisk together the all-purpose flour, cornmeal, sugar, baking powder, and salt.
• Combine Wet Ingredients: In another small bowl, whisk the lightly beaten eggs, buttermilk, and melted butter.
• Mix Batter: Pour the wet ingredients into the dry ingredients. Mix with a spatula or wooden spoon just until combined. It’s very important not to overmix; a few lumps are perfectly fine and will result in a more tender cornbread.
• Fold in Cheese: Gently fold in 1 ½ cups of the shredded cheddar cheese, reserving the remaining ½ cup for the top.

Step 7: Assemble and Bake the Casserole

Remove the skillet with the beef filling from the heat. If you are using a separate baking dish, transfer the filling into it now and spread it evenly. Drop spoonfuls of the cornbread batter evenly over the top of the hot beef filling. Use the back of the spoon or an offset spatula to gently spread the batter to the edges, covering the filling completely.

Sprinkle the remaining ½ cup of shredded cheddar cheese over the cornbread batter.

Step 8: Bake to Golden Perfection

Carefully place the skillet or baking dish into the preheated 400°F oven. Bake for 25-30 minutes, or until the cornbread topping is a deep golden brown and a wooden skewer or toothpick inserted into the center of the cornbread comes out clean. The filling should be hot and bubbly around the edges.

Step 9: Rest and Serve

Remove the casserole from the oven and let it rest for at least 10-15 minutes before serving. This crucial step allows the filling to set up and makes it much easier to serve clean, beautiful portions. The cornbread also continues to steam and become perfectly tender during this time.