Preheat the oven to 200˚C and add oil to a baking tray.

Prepare the basting sauce. Mix the soy and mirin. Set the mixture aside.

Lay the beef slices, place the asparagus, scallions and mushrooms. Roll them tightly, and secure with toothpicks.

Bake in the oven for 5 minutes and baste the beef rolls with the sauce. Repeat the basting every 5 minutes until the beef rolls are cooked.

Boil the remaining sauce lightly and brush the beef rolls again.

Top the rolls up with some chopped scallions ans serve.