5 boxes good milk chocolate biscuits, 48 biscuits in total (we used Marks & Spencer's All butter Fairtrade double chocolate chip cookies), or to make your own see tip, below
5 tbsp Baileys
5 tbsp icing sugar, sifted
Make your own cookies
Mix 250g plain flour, 300g golden caster sugar, 100g cocoa powder and half tsp salt in a bowl. Gently melt 100g dark chocolate and 100g butter together, then stir into the dry ingredients, followed by 2 large beaten eggs. Add chocolate chips if you wish, then space heaped tbsps of the mixture onto parchment-lined baking trays and bake at 180C/160C fan/gas 4 for 12-15 mins. Makes 48 cookies – enough for the pud.
Melt the chocolate and 150ml of the cream together in a small pan. Cool until spreadable, then use to sandwich pairs of the cookies together.
Choose a cake stand or flat plate to assemble your cake. Tip the remaining cream, the mascarpone, Baileys and icing sugar into a big bowl, and use an electric hand whisk to beat until thick and the mixture is just holding its shape.
Arrange some of your cookie sandwiches to make a base that almost covers the plate. Dot a little of the cream under each, and stick into position. Spread or dollop over a good layer of cream, then add another layer of cookies, a little smaller than the first. To get a neat finish, choose a front to your cake – and always start by arranging the outside ring of cookies from there (then you can snap cookies in half to fill in the middle). Repeat, making the layers smaller each time, until you finish with a single cookie and a dollop of cream on top! Chill in the fridge overnight.