1/4 cup brown sugar (packed)
1/4 cup reduced sodium soy sauce
2 teaspoons sesame oil
1/2 teaspoon crushed red-pepper flakes (or more to taste)
1/4 teaspoon ground ginger
1 tablespoon vegetable oil
3 cloves garlic (minced)
1 pound ground beef
2 green onions (thinly sliced)
1/4 teaspoon sesame seeds