In a small mixing bowl, whisk together the brown sugar, reduced sodium soy sauce, sesame oil, crushed red-pepper flakes, and ground ginger.

Place a large cast iron skillet over medium-high heat and add the vegetable oil. Allow the oil to heat until shimmering.

Add the minced garlic to the skillet and sauté for about 1 minute until fragrant, stirring constantly.

Add the ground beef to the skillet, breaking it up with a spatula. Cook for 3-5 minutes until browned.

Pour the prepared sauce over the browned beef and add the chopped green onions. Cook for an additional 1-2 minutes until the sauce thickens slightly.

Scoop the beef mixture into bowls, garnish with additional green onions and sesame seeds if desired.