Divide the enoki mushrooms into small bunches. Lay a slice of beef flat, place a mushroom bundle on one end, and roll tightly. Repeat until all mushrooms are wrapped.

In a bowl, whisk together the dashi broth, mirin, soy sauce, sugar, and black pepper until well combined. Set aside.

Heat olive oil in a skillet over medium heat. Add the sliced yellow onions and sauté for 3-5 minutes until softened and golden.

Arrange the prepared rolls over the caramelized onions. Drizzle with the prepared sauce and cover. Cook for about 3 minutes, flip, and cook for 1-2 more minutes.

Whisk the eggs until beaten. Pour over the rolls, cooking for about 2 minutes until the eggs firm up.

Transfer the rolls to a platter, garnish with green onions and sesame seeds, and serve hot with steamed rice.