Melt the butter. Blitz the biscuits in a blender and add the butter. Press this into steel rings so it is around half a centimetre thick all over.
Preheat oven to 170'C.
Separate the eggs. Whisk together the egg whites and the sugar until you have soft peaks. In a separate bowl whisk together the creme fraiche, ricotta, yogurt and egg yolk. Fold the egg whites into the mixture. Fill the rings with the mixture.
Bake in the oven for 20 minutes or until firm.
Remove and allow to cool topping with the caramel.
Put the sugar in a pan over a high heat, when you see the sugar melting lower the heat to medium. Do not sir the sugar. Tilt the pan to move the sugar.
When completely melted and you have a lovely golden caramel remove from the heat and whisk in the raspberries, Grand Marnier and butter. Allow to cool for a few minutes before spooning on top of the cheesecake.
«If you did not want to make the caramel a good quality raspberry jam will work equally well.»