Here's how to prepare the cake with cold yogurt. First you have to chop the biscuits very finely with a kitchen mixer and mix them with butter in a fairly large bowl.
Obtain a hinged opening cake pan 24 or 26 cm in diameter and cover it with baking paper: first the base cutting the excess with scissors, then the edges with a strip of the same baking paper. Then put the dough of biscuits and butter as the base of the cake, compacting it well with your hands or with the help of a meat tenderizer. Leave to rest in the fridge.
Put the gelatine sheets in cold water for 10 minutes. Meanwhile, sieve the icing sugar and mix it with the yogurt. When the gelatin has softened, squeeze it and put it in a saucepan with a spoonful of water; heat it over very low heat and stir continuously with a wooden spoon to prevent it from sticking or burning.
When the gelatine has melted, add it to the yogurt and mix well. Now pour the yogurt into the cake tin with the biscuit base and let it rest in the fridge for at least 3 hours.
Once the necessary time has passed, carefully open the hinged cake pan and carefully remove the parchment paper from the edges of the cake. You can leave the cake with cold yogurt in the cake tin or transfer it to a plate by removing the parchment paper underneath it.
Warm and melt in a bain-marie - or over a very low heat - the dark chocolate that you will use to decorate the cake: with a wooden spoon, pour it over the cake. Leave the cold yogurt cake in the refrigerator until ready to serve.
Ingredients for 12 people:
1 kg of coffee yogurt
200 g of shortbread biscuits
4 sheets of food gelatin
100 g of butter
30 g of dark chocolate
25 g of powdered sugar
