COMBINE: In a glass measuring cup, combine the brown sugar, soy sauce, gochujang, rice vinegar, toasted sesame oil, ginger, crushed red pepper flakes, and white pepper. Whisk with a fork and set aside for now.
SAUTE: Heat a 12-inch wok or skillet over medium-high heat. Add the ground beef, cook and crumble the meat for 4-5 minutes or until the meat is no longer visibly raw. Add the white parts of the scallions and garlic and cook for 2 minutes or until the scallions start to soften.
SIMMER: Lower the heat to low, pour the sauce over the ground beef, stir to combine. Let the mixture simmer for 4-6 minutes or until the sauce thickens and clings to the ground beef. Remove from heat. Top with the green portion of the scallions or sesame seeds.
SERVE: Serve in bowls over prepared jasmine rice with the cucumber salad (see notes.)
