Ingredients for the dough
Smash the biscuits. You can either use a crusher or a mortar, but if you have neither you can put the biscuits in a thicker nylon bag and smash them with a rolling pin.
Boil some water in pot. Place a smaller pot on top the other, so its bottom will be heated by the steam produced by the water. Put the chocolate in the smaller pot and melt it completely. Take it off the stove and put the butter in the chocolate. Mix them completely.
Put the biscuits, the sugar and the melted chocolate and butter in a bowl and mix them.
Preheat the over to 300 F (~150 C). Cover the bottom of your cake mould with baking paper. Put away 1/3 of the biscuit mix, and put the rest into the mould. Press it down a little to make the dough stick together. Bake it for 30-35 minutes on 280 F (~140 C).
Ingredients for the filling
The cake is gonna be filled with two kinds of filling. A strawberry jelly and a creamy, Mascarpone filling. I haven't found really good fresh strawberries, so I bought a pack of frozen ones. They are ugly but taste really good.
Unfreeze the frozen strawberries and let them drip the extra water. (If you are using fresh ones, wash them and cut off the green parts.) Mush them in a blender. Add one pack of gelatine (follow instructions of the package!) and the confectioner's sugar. Mix them well.
If you don't want to deal with the strawberry jelly, just buy a pack of instant jelly and use that. Won't taste as good though.
Whip the cream and add the gelatine and Mascarpone (add some sugar if the cream is not sweet enough). Stir in some vanilla extract too. When the cream is stiff enough stir in the remaining biscuit mix with a spoon.
Let the biscuit base cool and remove the baking paper. CAREFUL THERE. This stuff can break very easily! But it won't stick to the paper. So you can try and separate the paper from the biscuit layer with a knife. But if you are scared of this procedure you can just leave the paper on if that doesn't bother you.
Take off the edge of the mould and cover the inside with plastic foil (so the cream won't stick to the mould). Put the edges back. Put half of the cream in the mould and spread it. Now spread the strawberry jelly on top of that. You should put the thing in the fridge for a few minutes to make the jelly harder and then spread the other half of the cream on top of it.
Put the cake in the fridge for at least an hour. Decorate with whipped cream or fondant.