In a large skillet over medium-high heat, add the ground beef and cook, breaking it apart with a spatula, until browned and cooked through, about 6-8 minutes.
Drain excess fat from the skillet if necessary.
Add the minced garlic and grated ginger to the beef and cook for 1 minute until fragrant.
In a small bowl, whisk together soy sauce, brown sugar, sesame oil, crushed red pepper flakes, and black pepper.
Pour the sauce over the cooked beef and stir well to combine.
Reduce heat to medium and simmer the beef mixture for 5-7 minutes until the sauce thickens slightly.
Remove the skillet from heat and let the beef cool completely before assembling freezer portions.
Divide the cooked rice evenly among four freezer-safe containers.
Top each portion of rice with an equal amount of the Korean beef mixture.
Seal the containers and freeze for up to 3 months.
To serve, thaw the beef bowl in the refrigerator overnight and reheat in the microwave until hot.
Garnish with sliced scallions and toasted sesame seeds before serving.