1. Boil water in a small saucepan and blanch carrot sticks for about 2 mins, then add in the green beans to blanch for another 2 more mins. Drain and set aside to cool.
2. Place a slice of meat on the cutting board and season with salt and pepper on both sides. Next, place a few blanched carrot sticks, green beans and enoki mushrooms together on one end of the meat and roll it up.
3. Add cooking oil to a frying pan (with lid) on medium heat and pan-fry the beef rolls until all sides are nicely browned.
4. With the beef rolls still in the pan, add sake to the pan. Cover and cook until the sake has evaporated. Then, pour in the teriyaki sauce and sugar and turn the beef rolls until all sides are well coated with sauce. Transfer to a plate.
5. With the remaining teriyaki sauce in the pan, continue cooking to reduce to a thick sauce. Then return the beef rolls to the pan and fully coat them in the thickened sauce again. Serve immediately.