I made a cake. Polly hated it. You may or may not.
180g bourbon biscuits, blitzed. This was half a pack, less one – you know, to check they were ok.
75g butter, melted.
750g mascarpone. I actually used 500g plus 100g own brand soft cheese and a tablespoon of creme fraische.
4 limes – zest and juice.
5 tablespoons icing sugar. Depending on your personal taste you may want to start with four, taste after mixing and add more if you think.
Chocolate to decorate. I melted 2 squares of 70% cocoa in and bag, intending to pipe a pattern on. The “pattern” turned out to be uneven blobs.
Mix the melted butter into the blitzed bourbon biscuits. When it feels sufficiently muddy, spread over the bottom of a 20cm tin of appropriate type to later release the cake. Flatten. Fridge the tin.
Blitz the mascarpone (or substitutes), lime juice, icing sugar and lime zest (you may wish to reserve some for decoration), then smear over the chilled base. Smooth the top, and refrigerate again.
Chill for about 4 hours. At some point before serving, decorate the top. I botched it with melted chocolate and threw on remaining lime zest.