2.5 cm (1 inch) piece of fresh root ginger, peeled and finely grated
1 garlic clove, crushed
crudités, such as carrots, sugar snap peas and cucumber
6 tablespoons crunchy peanut butter
3 tablespoons dark soy sauce
1 small red chilli, finely chopped
150 ml (1/4 pint) boiling water
Cut the steak into long, thin strips. Mix together the soy sauce, oil, vinegar or mirin, sugar, ginger and garlic in a non-metallic bowl. Add the steak and toss well to coat. Cover and leave to marinate for 15 minutes.
Meanwhile, heat all the ingredients for the sauce in a pan over a very gentle heat, stirring constantly with a wooden spoon, until smooth and thick. Transfer to a small serving bowl and place on a serving platter with the crudités.
Thread the beef on to 8 metal skewers, or bamboo skewers presoaked in cold water for 30 minutes, and cook under a preheated high grill for 2 minutes on each side until browned and just cooked.
Transfer to the serving platter with the sauce and crudités and serve immediately.