Cheshire and Cumbria are famous for their damsons, especially the Lyth Valley area, where they are large, juicy and much sweeter than elsewhere. Lyth Valley damsons are often eaten raw, like grapes, with Lancashire cheese. Locally they are called Witherslack damsons.
Put the damsons in a saucepan with the sugar and lemon and enough water just to cover. Simmer until soft. Leave until they are cool enough, then lift them out and remove the stones. Blend in a liquidiser or food processor and turn into a large bowl.
Fold in two-thirds of the whipped cream and all the egg white lightly but thoroughly into the damsons seeing that you make sure you get right to the bottom and that the mixture is an even colour. Transfer the mixture to a serving bowl, decorate the top with the macaroons and dot all over with the remaining whipped cream.