Preheat the oven to 375°F and lightly grease a 12-cup muffin tin.
In a mixing bowl, combine the ground beef, egg, diced onion, taco seasoning, 1/2 cup of the cheddar cheese, and 2 tablespoons of the cilantro. Mix until evenly blended.
Divide the mixture into 8 equal portions and press each into a muffin cup to form mini loaves.
Bake for 20 to 25 minutes until the internal temperature reaches 160°F and the tops are lightly browned.
While the meatloaves bake, mash the avocados in a bowl. Stir in the sour cream, lime juice, salt, and remaining cilantro until smooth.
Remove the meatloaves from the oven and sprinkle the remaining 1/2 cup cheese over the tops. Let them rest for 5 minutes.
Serve each meatloaf with a spoonful of avocado crema.