In a large skillet cook the ground beef and garlic breaking it into crumbles over medium heat until no longer pink. Add the stir fry vegetables to the pan and saute 2-3 minutes or until tender.
In a small bowl whisk brown sugar, soy sauce, sesame oil, ginger, red pepper flakes and pepper. Pour over the ground beef mixture and let simmer for another minute or two.
Serve over hot rice and garnish with green onions and sesame seeds.