Cut lime in half and squeeze juice over the avocados.
Scoop out some of the avocado to create a larger hole to fill.
Reserve excess avocado for later.
Heat olive oil in a medium frying pan over medium heat. Add diced onion and saute for 3-5 minutes, until tender and translucent.
Add ground beef and brown until fully cooked (about 5-6 minutes).
Pour in taco seasoning and add salt and pepper to taste, stirring thoroughly. Drain away any excess fat or liquid from the pan and remove from heat.
Begin filling each avocado with the taco meat, remaining avocado, shredded cheese, lettuce, tomatoes, and garnish with sour cream and cilantro.
ENJOY!