Preheat your oven to 350°F (175°C).
In a large skillet over medium heat, add the ground beef and cook until browned. Add diced onion and minced garlic, cooking until the onion is translucent.
Stir in black beans, corn, diced tomatoes, chili powder, cumin, and season with salt and pepper. Let it simmer for about 5 minutes, then remove from heat.
In a mixing bowl, whisk together the corn muffin mix, milk, and egg until combined.
In a greased 9x13 inch baking dish, spread half of the corn muffin mixture evenly on the bottom.
Layer the meat and bean mixture over the corn muffin crust.
Pour the remaining corn muffin mixture over the beef filling, spreading it evenly to cover.
Sprinkle shredded cheddar cheese on top.
Cover the dish with aluminum foil and bake for 30 minutes. Then remove the foil and bake for an additional 15 minutes, or until the top is golden brown.
Once done, let it cool for a few minutes before serving.