Bring a medium pan of water to the boil, then carefully lower in the eggs and cook for 9 mins. Remove to a bowl of iced water using a slotted spoon and leave to stand for 10 mins until cold. Peel, then finely chop.

Tip the chopped egg into a bowl along with the prawns. Stir in the mayonnaise and lemon juice, then season with salt and pepper.

Toast the bread, then butter it. Spoon over the prawn and egg mayonnaise, then sprinkle with some chives and serve.