1. Preheat your oven to 400°F and grease a 9×13 inch baking dish.
2. In a large skillet over medium heat, cook the ground beef until it’s no longer pink. Drain off any excess fat.
3. Stir in the taco seasoning and water, and let it simmer for a few minutes until it thickens slightly.
4. Add in the diced tomatoes, black beans, and corn, and cook for another 2-3 minutes until everything is heated through. Spread this mixture evenly into the bottom of your baking dish.
5. In a bowl, mix together the corn muffin mix, egg, and milk just until combined (don’t overmix). Spoon the cornbread batter over the beef mixture in the dish.
6. Bake for about 15 minutes. Then sprinkle the shredded cheddar cheese evenly over the cornbread layer and bake for another 10-15 minutes or until the cornbread is done and the cheese is bubbly.
7. Let the bake stand for a few minutes before serving. Garnish with the chopped green onions and cilantro, if using.
