Heat the oil in a large skillet over medium heat. Add the ground beef and cook until no pink remains.
Meanwhile, in a bowl or large measuring cup, whisk together the soy sauce, sesame oil, sesame seeds, garlic, and brown sugar.
When the beef is cooked, add the soy sauce mixture and stir for a few minutes until beef is well coated and most of the liquid is absorbed.
Serve bulgogi over rice with green onions and sesame seeds for garnish.
Notes
Leftover ground beef bulgogi will keep in the fridge for up to 3 days, and reheats well on the stove top or in the microwave.For extra flavor and a silky sauce, top the bulgogi with a fried or poached egg.