Preheat the oven to 375°F and lightly grease 8 cups of a muffin tin.
In a mixing bowl, combine the ground beef, taco seasoning mix, breadcrumbs, egg, half the cheddar cheese, and salsa. Stir until evenly mixed.
Divide the meat mixture evenly into the 8 prepared muffin cups and press down lightly to shape.
Bake for 20 minutes until the meat is cooked through.
Sprinkle the remaining cheddar cheese over the tops and return to the oven for 2 minutes until the cheese melts.
Remove from the oven, let rest for 3 minutes, then garnish with cilantro and serve with sour cream on the side.