The rolls are tasted between a mixture of salty and sweet since the sauce I have used is teriyaki sauce which I think is a good match with a bowl of rice for a simple dinner night. This dish contains 2 simple ingredients, thin slices of beef and enoki mushroom. The procedures are super easy and quick, it takes about 15 minutes from preparation to serve. Sounds easy and good? Let's cook!

Tips:
Thicken the sauce by cooking it for extra long time. This could cause the sauce become thicker. Don't over cook the sauce - taste the sauce while you cook it. It will taste really salty when you overcoook it.
You can use corn starch (2:1 ration of water : corn starch) mixture to thicken the sauce. A quicker way to create the sauce.
If you don't have sake, you can substitute with Chinese rice wine or dry sherry. But if you can't take alcohol, substitute it with water.
If the beef slices are too thin and break it easily, I suggest you to use two slices of beef instead of one.