1.Combine the garlic, ginger, soy sauce, sake, mirin, and sesame oil in a shallow dish. Place beef slices into dish and coat evenly in the marinade. Place in fridge for a minimum of 30 minutes.
2.Slice the roots off of the enoki, leaving enough at the bottom so the mushrooms are still stuck together. Break into small sections and place into a bowl of lukewarm water. Sprinkle with a generous pinch of salt and let sit for 15 minutes. Drain.
3.On a clean surface, stretch out one slice of beef. Top with two sections of enoki facing opposite directions. Roll the beef tightly around the enoki on a slight diagonal, so it’s wrapped evenly. Repeat for remaining slices of beef.
4.Heat vegetable oil in a large pan over medium high heat. Add the rolls and cook quickly, rotating every few minutes until browned.
5.Once cooked, remove from pan and transfer to a serving plate. Pour any remaining marinade into the pan and cook until sauce has thickened. Pour sauce on top of beef rolls and serve immediately.