Step 1: Preheat your oven to 375°F (190°C). Lightly grease a 12-cup muffin tin.
Step 2: In a large skillet over medium heat, cook the ground beef (or turkey) until thoroughly browned. Drain any excess fat.
Step 3: Stir in the taco seasoning and 1/2 cup water. Bring to a simmer and cook for 5 minutes, allowing the sauce to thicken.
Step 4: Add the rinsed black beans, corn, and diced tomatoes to the meat mixture. Stir to combine and cook for an additional 2-3 minutes until heated through. Remove from heat.
Step 5: Unroll the crescent roll dough and separate it into 8 triangles.
Step 6: Press each crescent roll triangle into the prepared muffin tin cups, pressing it into the bottom and up the sides to form a cup. Pinch any seams together to prevent leaks.
Step 7: Spoon the prepared taco filling evenly into each crescent dough cup, filling generously.
Step 8: Sprinkle about 1-2 tablespoons of shredded cheddar cheese over the filling in each cup. If desired, sprinkle with chopped green onions.
Step 9: Bake for 12-15 minutes, or until the crescent dough is golden brown and the cheese is melted and bubbly.
Step 10: Carefully remove the muffin tin from the oven and let the taco cupcakes cool for a few minutes before transferring them to a wire rack.
Step 11: Serve warm with your favorite toppings such as sour cream, salsa, diced avocado, fresh cilantro, or sliced jalapeños.