Vegetarian spring rolls

Name: Vegetarian spring rolls
Ingredients: 1 tbsp groundnut oil; 1 tsp grated, peeled fresh root ginger; 100g/3½oz fresh shiitake mushrooms or soaked porcini mushrooms, sliced, stalks removed; 100g/3½oz tinned bamboo shoots, drained and cut into matchsticks; 50g/1¾oz tinned water chestnuts, drained, sliced into small strips; 2 tbsp low-sodium, light soy sauce; 1 tbsp Chinese five-spice powder; 75g/2¾oz beansprouts, must be very fresh; 2 leaves of cavolo nero, washed, shredded; 2 large spring onions, sliced lengthways; 1 small carrot, peeled, cut into matchsticks; 1 tbsp of oyster sauce or vegetarian oyster sauce; 1 tsp toasted sesame oil; pinch sea salt; pinch ground white pepper; 25-30 large spring roll wrappers (15x15cm/6x6in square), frozen variety, defrosted (see tip); 1 medium free-range egg, lightly beaten; peanut oil, for deep-frying; Thai sweet chilli sauce, to serve