Dan Lepard's chequerboard biscuits and dark chocolate mousse recipe

This intense chocolate dessert makes a good finale to our Short & Sweet adventure. See Fiona Beckett's column for what to drink with it. For each dough layer 175g 00 pasta flour 75g icing sugar 100g cold unsalted butter, cubed ¼ tsp salt Plus either 1 vanilla pod or 25g cocoa (see instructions) For the mousse 3 egg whites 50g caster sugar 175g dark chocolate 25ml brandy 25ml boiling water To start off, you need to make two lots of biscuit dough, one flavoured with vanilla, the other with cocoa. For the vanilla dough, mix one batch of flour, icing sugar, butter and salt with the seeds from the vanilla pod and rub together. Work the mixture until it warms slightly and turns to a firm dough. For the chocolate dough, mix a second batch of flour, icing sugar, butter and salt, only this time replace 25g flour with 25g cocoa. Work together in the same way. Line the base of an 18cm square tin with nonstick paper, pat the vanilla dough evenly into it, then flip it out on to a worksurface. Repeat with the chocolate dough, then lightly brush water on top of one sheet of dough and squarely lay the other on top of it. Use a rolling pin to seal, then cut into thirds. Brush each third lightly with water and stack in alternating chocolate and vanilla layers. Wrap and chill for 30 minutes. Cut lengthways into 1cm slices, moisten again and stack alternately in layers. Wrap and chill once more, then cut into 0.5cm chequerboard slices. Lay on a tray lined with nonstick baking paper and bake at 160C (140C fan-assisted)/320F/gas mark 2½ for 20-25 minutes, until crisp and barely golden. For the mousse, briskly stir the egg whites and sugar over a gentle heat until about to set and piping hot (this kills any bugs), then whisk to a thick, light meringue. Melt the chocolate, stir in the brandy and boiling water, fold in the meringue, spoon into ramekins, cover and chill to set. Serve with the biscuits for dunking. • Dan Lepard's book, Short & Sweet, is published by Fourth Estate at £25. To order a copy for £16 (including mainland p&p), go to the Guardian Bookshop. danlepard.com/guardian