6 large crisp lettuce leaves
2 tablespoons vegetable oil
4 spring onions, finely chopped
1 teaspoon ground ginger
1 celery stalk, finely chopped
75 g (3 oz) mushrooms, finely chopped
50 g (2 oz) canned water chestnuts, drained and finely sliced
100 g (4 oz) long-grain rice, cooked
100 g (4 oz) frozen peas, cooked and drained
1 1/2 tablespoons soy sauce
1 egg, beaten extra soy sauce, to serve