In a medium non-stick skillet, over medium heat, add oil, and once warm cook onion until translucent and soft. Around 3 to 5 minutes.
Add ground beef, season with salt and pepper. Cook the ground beef, breaking it up into small pieces throughout, until browned and no longer pink.
Add the brown sugar, garlic powder, cayenne pepper, tomato sauce, and soy sauce.
Stir for 2 to 3 minutes until well combined and remove from heat.
Assembling the lettuce wraps by dividing the beef filling between 8 lettuce leaves and then top with shredded red cabbage and carrots.