Warm a large skillet over medium high heat. Add the ground beef and break it up with a spoon as it browns. Let it sit in the hot pan for a minute or two at a time to get browned bits.

Stir in the onion and cook until softened, about 3 minutes. Add the garlic and ginger and cook just until fragrant.

In a small bowl, whisk the soy sauce, brown sugar, gochujang or sriracha if using, sesame oil, and rice vinegar. Pour this sauce over the meat. Let it bubble and reduce for 2 to 3 minutes until glossy and clinging to the beef.

Taste and adjust the seasoning as needed. Finish with chopped green onions and sesame seeds.

Scoop over warm rice and add quick cucumber slices or kimchi for crunch and zing.