This is a quick and easy dish to make. Just make sure to slice the beef very thin. I find it easier if I freeze it for 1/2 hour first. I serve it over rice.
Combine yellow onion, white and light green parts of green onions, soy sauce, sugar, sesame seeds, garlic, sesame oil, red pepper flakes, ginger, and black pepper in a bowl until marinade is well mixed. Add steak slices to marinade; cover and refrigerate, 1 hour to 1 day.
Heat a skillet over medium heat. Working in batches, cook and stir steak and marinade together in the hot skillet, adding honey to caramelize the steak, until steak is cooked through, about 5 minutes. Garnish with green parts of green onions.