Take each slice of beef and wrap it around a small bunch of enoki mushrooms (~10 enoki mushrooms) to form a tight roll. Repeat until all beef and mushrooms are used up.
Heat the oil in a large pan over medium-high heat. Once the pan is hot, place the beef rolls seam-side down and sear for 3-4 minutes, turning until all sides are browned and crispy. Remove the rolls from the pan and set aside.
In the same pan, add more oil if needed, then add minced garlic over medium heat and cook for 30 seconds until fragrant. Pour in the soy sauce, mirin, sugar, rayu, and rice vinegar. Stir and simmer for 1-2 minutes until the glaze slightly thickens.
Return the beef rolls to the pan, turning them gently to coat evenly in the glaze. Let them cook in the glaze for an additional 1-2 minutes, allowing it to reduce slightly and cling to the rolls.
Drizzle the rolls with more rayu for extra spice, sprinkle with shichimi togarashi, and top with sliced scallions if using. Serve the beef enoki rolls over a bed of the rice.