Place the egg yolks and mustard into a food processor and blend until pale and creamy. With the motor running, pour in enough oil, in a steady stream, until the mayonnaise is thick.

Then add the Worcestershire sauce, Tabasco, brandy and tomato ketchup. Check the seasoning, add a squeeze of lemon juice, adjust seasoning to taste and mix well. Cut the remaining lemon into 4 wedges.

Place the sliced salad leaves into the serving glasses, combine the peeled prawns with a few tablespoons of the dressing and season to taste. Add on top with the remaining sauce a pinch of cayenne, sprinkle with mustard cress

To make the melba toast, put the bread onto a baking tray, toast under a hot grill on both sides. Remove the crusts and the slice through the bread horizontally. Rub the underside on the board to remove any excess crumbs, cut each piece into two triangles put back on the tray untoasted side up and toast until golden.

Serve alongside the cocktail with the lemon wedge and the prawn hung over the glass edge.