'Lumpia' Filipino-style spring rolls

Ingredients

• 300 grams minced pork
• 300 grams finely chopped green (uncooked) prawn meat
• 1 eschalot, chopped finely
• 2 tbsps finely chopped garlic chives
• 1 cup (60g) shredded wombok
• 2 tsps oyster sauce
• 2 tsps soy sauce
• 2 tsps cooking sake
• 2 egg yolks
• 1 tbsp finely grated ginger
• ¼ tsp caster sugar
• 30 sheets frozen square spring roll wrappers, thawed, halved
• Vegetable oil, for deep frying
• Sweet and sour sauce, to serve