Heat a large skillet over medium heat. Add 2 cups of chopped beef and cook for about 8–10 minutes, stirring occasionally, until browned.

Once the beef is cooked, sprinkle in 1 teaspoon of salt and 1 teaspoon of pepper. Stir well to combine and cook for an additional minute.

Arrange 4 slices of your favorite cheese on top of the beef. Cover the skillet and cook for another 2–3 minutes until melted.

While cheese is melting, take 4 toasted sandwich rolls and place them on a cutting board. Optionally toast in the oven at 350°F for 5–7 minutes.

Use a spatula to scoop portions of the beef and cheese mixture onto each toasted sandwich roll.

Top each sandwich with avocado slices, fresh salsa, and pickled onions. Add a dollop of sour cream if desired.

Serve immediately while warm, either on a platter for sharing or individually.