Julienne the ginger.

In a pot, heat all ingredients for the beef shigure-ni except the beef over medium heat until boiling. Add the beef and cook while stirring until the liquid reduces. Let cool to allow flavors to meld.

Heat vegetable oil in a frying pan over medium heat. Crack the eggs into the pan and cook until the edges are browned. Flip and cook until the other side is browned.

Place a sheet of plastic wrap on a surface. Lay a sheet of nori in the center, then layer 1/4 of the rice, lettuce, half of the beef shigure-ni, a fried egg, lettuce, and another 1/4 of the rice. Fold the edges of the nori over the filling. Repeat for the second onigirazu.