Heat a large skillet over medium-high heat. Add the ground beef and break it up with a spatula. Cook until browned, 4–5 minutes. Drain excess fat if you must, but don’t go full dehydration mode.
Push the beef to the side. In the same pan, add a splash of oil if needed and sauté the garlic, ginger, and onion until fragrant, about 2 minutes. Smells like a dinner plan arriving on time.
Stir the beef back in. Add soy sauce, brown sugar, sesame oil, rice vinegar, and gochujang. Mix well to coat every crumb. Cook 2–3 minutes until the sauce thickens a bit and everything sticks together like a team.
Taste and adjust. If it needs more sweetness, a touch more sugar; if it’s lacking heat, a pinch more gochujang or chili flakes. Quick rinse of the pan and you’re done—okay, not that quick, but close.
Remove from heat. If you like, garnish with sesame seeds and sliced green onions. Serve hot and watch it disappear.