Easy prawn cocktail

Method

1. For the mayonnaise, put the egg yolks into a roomy bowl and mix in the mustard and a little seasoning. Using an electric hand mixer on a slow speed, beat together while very slowly trickling in the sunflower oil. Once the mixture is becoming thick, add a little lemon juice. Continue beating, adding the oil a little more quickly and increasing the beating speed. Once the oil has been used up, add some more lemon juice, then begin incorporating the olive oil until you are happy with the taste (delicious. testers used about 75ml). Beat in a little cold water if the mayonnaise looks too greasy and shiny. Taste and add a final squeeze of lemon juice or seasoning if needed. Spoon into a lidded plastic pot and keep in the fridge until ready to use (see Make Ahead).
2. Put the shredded lettuce in a small bowl, then cover with cold water and a few cubes of ice (to help crisp the lettuce). Set aside while you make the cocktail sauce.
3. In another bowl, mix together the mayonnaise, ketchup, Tabasco and cognac. Mix in the spring onions and cucumber. Set aside.
4. Drain the lettuce and either spin dry, or put on a tea towel, gently roll it up, then tip out into a bowl. Divide the lettuce among 4 large wineglasses, top with the prawns, then spoon over the cocktail sauce. Garnish the rim of each glass with the lemon wedges and sprinkle the cocktails with a pinch of paprika.