In a bowl combine the mayo, sugar, gochujang, salt, and vinegar. Mix until well combined. Add the apple slices, cabbage, and sesame seeds. Toss until everything is coated and evenly distributed. Set aside to chill.
In a bowl, combine all patty ingredients and mix well. Leave to marinate for about 15 – 20 minutes.
Form the bulgogi mixture into medium-sized patties.
Fry or grill on medium heat for about 10 minutes on each side.
Toast buns in a pan over medium heat until crisp.
Make kimchi mayonnaise.
Take the toasted buns and place a layer of kimchi mayo on each side. Place a lettuce leaf on top of the mayo, followed by the bulgogi patty, then the apple coleslaw. Top with the top bun. Repeat for remaining burgers.
Serving Size 4-6 servings