For the base of 20 cm diameter you'll need: 150 g butter or digestive biscuits, 100 g butter. 

Chocolate filling: 280 g dark chocolate, 220 ml 38 % cream, 1,5 tbsp sugar and 45 g butter

Place a sheet of parchment paper into a baking tray and let the corners poke out of the tray, it will be easier to move the cake later. Crush the biscuits finely in a zip bag or a bowl with a rolling pin or a bottle of wine (as we did :), or if you've got a mixer, just mash them there. Melt the butter and pour it into the biscuits and then move the whole mixture in the tray and make a crust. Let it cool in the fridge.

Meanwhile, let's prepare the filling. Break the chocolate into pieces and put it in heat proof bowl. Bring cream, butter and sugar into a boil and when you see big bubbles, it is the right time to pour it into a bowl of chocolate. Cover the bowl and let it melt for a while. We chatted a little so I'm not sure how long we let it melt, but I assume that 5 minutes will do. Then you just mix properly and pour the chocolate mix in the biscuit base. Let the whole cake set in the fridge and then serve it to a birthday girl/boy. :-)

Special thanks to Laura for lending us the cake tin.