Pre heat the oven to 180c
In a bowl cream the butter with the icing sugar and salt until very creamy.
Add the egg yolk, vanilla and the Cointreau and mix well.
Sift the flour with the baking powder very well, twice.
Gradually with a wooden spoon add in the flour mix to the creamed butter. Fold in the pistachios and the cranberries, and mold the dough rolled in plastic wrap into a log of your desired shape.
Refrigerate the mix until firm, and then use a sharp knife to slice the log into the biscuits.
Place onto greased or lined baking tray. Bake in a moderate oven for 15 minutes until golden. Allow to cool on the tray and then dust in icing sugar to coat.
Store in an airtight container.