In a medium bowl, whisk together brown sugar, reduced sodium soy sauce, sesame oil, crushed red-pepper flakes, and ground ginger until fully combined. Set aside.

Heat vegetable oil in a large cast-iron skillet over medium heat. Add minced garlic and sauté for about 1 minute until fragrant.

Add ground beef to the skillet with the sautéed garlic. Break apart the meat and cook for 3-5 minutes until browned.

Once cooked, pour the prepared sauce over beef and add chopped green onions. Stir well and let simmer for 2 minutes.

Serve the beef mixture over steamed rice or in lettuce wraps, garnished with sesame seeds and extra green onions.