Place the butter in a bowl. Using the whisk on a hand mixer, beat the cane sugar, vanilla sugar, salt and egg until the mixture turns paler in colour.
Stir in the diced apple and all the other ingredients up to and including the nuts. Combine the flour and baking powder, mix in. Using a teaspoon, spoon out the mix into small and sufficiently well-spaced mounds on a baking tray lined with baking paper.
Cook for approx. 12 mins. in the centre of an oven preheated to 180°C. Remove from the oven, cool on a cooling rack and dust with icing sugar.