Chicken and vegetable spring rolls

Ingredients
1 tbsp groundnut oil, plus extra for deep-frying
200g/7oz skinless chicken breast fillets, chopped into small pea-sized pieces
4 dried Chinese mushrooms, soaked in hot water for 20 minutes, drained and finely chopped
1 tbsp light soy sauce
1 tbsp five-spice powder
1 tsp grated fresh root ginger
75g/3oz beansprout
2 large spring onions, finely sliced lengthways
1 small carrot, julienned
1 tbsp oyster sauce
½ tbsp light soy sauce sea salt and ground white pepper
16 ready-made large spring roll wrappers, thawed if frozen (available from Asian supermarkets)
1 egg yolk, beaten
Preparation method
1. Heat a wok until smoking and add the groundnut oil, then add the chicken and mushrooms and stir-fry for 1-2 minutes. Season with soy sauce and five-spice powder, then remove from the wok and set aside to cool for ten minutes. Wipe the wok clean with kitchen paper.
2. Place the grated ginger, beansprout, spring onions and carrot into a bowl, then add the chicken and mushrooms and season with the oyster sauce, soy sauce, sea salt and ground white pepper. Stir well to combine.
3. Lay two spring roll wrappers one on top of the other (the extra thickness will prevent the skin from breaking) and position so that the corners are pointing upwards, downwards and to the sides.
4. Spoon two tablespoons of the filling into the centre of the wrapper. Brush each corner of the wrapper with the cornflour paste, then bring the