Make the biscuits into powder using a kitchen chopper. To them add the heated butter and stir the mixture well.
Form a cake layer at the bottom of an oven dish and then leave the dish in the fridge for the layer to harden.
In the meantime, make a cream from the yoghurt, sour cream and brown sugar.
Put the dessert back in the fridge for several hours, it's then ready to eat.
You can make 1 whole cake or several portioned bowls.