Preheat oven to 375 degrees. Lightly coat a muffin tin with cooking spray; set aside.

In a large skillet over medium high heat, sauté onion in olive oil until translucent; about 5 minutes. Remove from heat and cool slightly before mixing with other ingredients.

Combine onion mixture with remaining ingredients in a large bowl, stirring just until combined. Press meatloaf mixture into muffin tin cups, filling to the rim. To allow for even baking, pour a little water into any cups that are empty. (This recipe should fill 8 regular size muffin cups.)

Bake for 15-20 minutes. Remove from oven and brush tops with more ketchup or barbecue sauce and sprinkle with a little cheese. Bake for 5 more minutes, Let rest 5 minutes before removing from muffin tin. (Drain meatloaf on a paper towel lined plate if necessary.)