Heat a large skillet over medium heat. Add the ground beef and cook, stirring occasionally, until cooked through, approximately 8-10 minutes.
While the beef is cooking, chop your bell pepper and onion.
Once the beef is cooked, drain excess fat. Add the onion and bell pepper. Cook until the vegetables are just softened, approximately 5 minutes.
Remove from heat. Add the cheese and stir until cheese is melted. Season to taste with salt and black pepper.
Scoop approximately 1/2 cup of the beef mixture into each lettuce leaf. Top with additional cheese if desired.
Notes
Use more or less beef mixture based on preference and how large your leafs are.Provolone is the traditional cheese used for cheesesteaks, but mozzarella is a great substitute.Typically provolone is found in slices. You can "shred" it by either freezing it and then grating it, or cutting it into small pieces 1/2" square or smaller. Leaving a slice whole will take longer to melt. Alternatively, you can also just lay a slice of provolone in the lettuce cup and put the cheeseless meat right on top.