Dice onion and pepper into small pieces.
Heat olive oil in a skillet, add onions and peppers, and cook on medium for 4 minutes.
Add ground beef and cook until fully cooked.
Pour off any excess grease and return the skillet to the stovetop.
Add ketchup, brown sugar, Worcestershire, apple cider vinegar, diced banana peppers, and salt and pepper.
Heat on high for 2-3 minutes.
Reduce heat to a simmer and cook for 15 minutes.
Serve on sesame seed buns and garnish with banana peppers.