Heat sesame oil in a skillet over medium heat. Sauté garlic and ginger until fragrant. Add ground beef, cooking until browned and cooked through. Drain excess fat.
Stir in soy sauce, brown sugar, and hoisin sauce. Simmer for 2–3 minutes, combining the flavors well.
Boil ramen noodles per package instructions. Drain and set aside.
Add boiled noodles to the beef mixture in the skillet. Pour in beef broth and toss everything together. Add green onions and red pepper flakes, tossing over medium heat until noodles are well-coated.
Serve hot in bowls. Garnish with bell peppers, carrots, and sesame seeds if desired.
Notes
Store leftovers in an airtight container in the fridge for up to 3 days. For a fresh meal, reheat with a little additional beef broth or water.