Katsu sandos

Ingredients

• 25g white cabbage , finely shredded -
• 25g red cabbage , finely shredded -
• 1 tbsp white vinegar -
• 2 tbsp plain flour -
• 1 egg , beaten -
• 150g panko breadcrumbs -
• 80g piece pork escalope or 3-4 mini chicken fillets, bashed flat -
• 6 large peeled raw prawns , halved to give 2 thin slices each -
• cold pressed rapeseed oil , for frying -
• 2-4 tbsp mayonnaise -
• 4 slices white bread -
• 2 tbsp ketchup -
• 1 tbsp Worcestershire sauce -
• 1 tsp soy sauce -
• 1 tbsp golden caster sugar -
• ¼ tsp mustard (yellow or Dijon) -
• ½ tsp white vinegar -