Keep the beef frozen and do not thaw
Rinse and trim the root ends off the enoki mushrooms and separate into small bundles
Insert each bundle straight into a frozen beef roll without unraveling
Mix water, dashi powder, soy sauce, mirin, and sugar to make the sauce
Heat a pan over medium-high heat, add sliced onion, and sauté 2-3 minutes until softened and fragrant
Place beef rolls directly on top of the onions
Pour in the sauce, cover, and let simmer for about 3-4 minutes
Lower heat to medium and slowly pour whisked eggs evenly over the beef
Cover and cook 1-2 minutes, just until the eggs are softly set
Garnish with green onions and sesame seeds and serve as-is or over rice
