Ingredients (serves 2):
In a small pan, add sake, soy sauce, sugar, gochujang, onion, garlic, ginger and black pepper. Bring to a boil over medium heat. Remove from heat and set aside to cool.
Slice beef against the grain to 1/8-1/4 inch slices.
Hint: Depending on the cut of meat used, adjust thickness of each slice. Slice thinly for tougher cuts like loin filet, and slice thicker for tender cuts like flanks.
In a plastic bag, add sliced beef, potato starch and half the amount of sauce from step 1. Distribute starch and sauce with fingers over the bag and marinate for 15 minutes to up to one hour.
When meat is marinated, fill serving bowls with warm rice and top with hand torn green leaf lettuce, set aside.
Heat sesame oil and vegetable oil in a frying pan over medium heat.
Add marinated beef and cook for 40 seconds, then flip the meat and cook for another 10 seconds or until browned on both sides.
Distribute cooked beef over the rice bowl, drizzle remaining sauce from step 1 and sprinkle sesame seeds.