Preparation

For the chocolate biscuit

1. Weigh chocolate into the bowl. Chop 10 seconds on speed 6.
2. Melt 5 minutes, at 37°C on speed 1.
3. Add butter. Mix 2 minutes on speed 4.
4. Scrape down sides of the bowl with spatula. Mix 20 seconds on speed 4.
5. Add sugar. Mix 2 minutes on speed 5.
6. Add egg and vanilla. Mix 30 seconds on speed 5.
7. Add all remaining Ingredients. Mix 1 minute on Dough speed, pausing to scrape down sides if necessary.
8. Tip out onto a long piece of cling film and shape into a log about 30 cm long, using the cling film to wrap the log. Chill until firm, at least 4 hours in the fridge.
9. When ready to bake, slice 3 mm thick biscuits and place on baking parchment on a rimless baking tray, leaving 2 cm between the biscuits as they will spread a little.
10. Bake 1 sheet at a time, about 9 minutes for 7 cm biscuits, and about 12 minutes for 10 cm biscuits. Bake in preheated oven at 180°C.
11. When you take the biscuits out of the oven, slide the whole piece of baking parchment onto the wire rack and leave until the biscuits are cool. Lift biscuits off the paper with a flat knife. Store in an airtight box or tin.

For the cream cake

1. Whip 500 ml double cream until softly whipped, adding a little sugar or a liqueur (about 2 Tbsp) to flavor the cream if desired.
2. Spread a 3mm layer of cream onto each biscuit then stack them together to form a log. Cover the log with the remaining whipped cream and put into the fridge.
3. Serve after 2 to 6 hours – this will allow the biscuits to soften slightly. Slice the log on the diagonal so all the stripes of the biscuits can be seen.