BBC Food - Recipes - Prawn and langoustine cocktail

Ingredients

• 600g/1lb 5oz raw tiger prawns , shell on
• 600g/1lb 5oz raw langoustines , shell on
• 2 free-range egg yolks
• 1 tsp Dijon mustard
• 300ml/10fl oz vegetable oil
• 1 tsp Worcestershire sauce
• 4 dashes Tabasco sauce
• 25ml/1fl oz brandy
• 50ml/2fl oz tomato ketchup
• salt and freshly ground black pepper
• 1 lemon
• 3 heads Little Gem lettuce , leaves separated
• 2 tbsp French dressing
• ½ tsp cayenne pepper
• 2 tbsp mustard cress
• 8 slices buttered brown bread