First, make a mascarpone cream. Mix together mascarpone, sifted powdered sugar, and some ground tonka bean. Fold in beaten whipping cream and put it in the fridge.
Put hazelnuts in a large frying pan without adding any oil. Stir frequently and make sure they don't burn. While they're still warm, remove the skins and chop them roughly. Set them aside.
Combine together wine, water, sugar, and spices in a medium-sized pot. Bring to a boil and stir occasionally and then turn down the heat a little bit.
In the meantime, halve the fruit and remove the pits. When the liquid comes to a boil, put the fruit in a pot and cover it with the lid. It is important that the liquid covers the fruit completely and that fruit cooks at a temperature that is slightly under boiling point.
Fruit is done when you can easily pierce it with the fork but it's not falling apart. When the fruit reaches the softness that suits you, remove it and put it aside. Increase the heat a bit and let the liquid reduce until it is thick as syrup.
Now you are ready for serving. First, spread some hazelnuts, then place the fruit on it along with some mascarpone cream. Finish by sprinkling some hazelnuts over the top.