Heat your oven to at least 160C
Put 25g of icing sugar and the pistachios in a blender and whizz until fine. Mix with 175g more icing sugar in a large bowl.
Whisk the egg whites until you form stiff peaks. Add 50g icing sugar and whisk again until thick and glossy.
Fold in the nut mix. Spoon into a piping bag or like I did use a spoon to form small rounds of the mixture on parchment lined trays. Each one should be about the size of a 10 coin but I made mine on the large side.
Leave them to dry for 30 mins before putting them in the oven, bake for 12-15 mins or until golden brown.
Beat together the cream cheese and melted chocolate, use this mix to sandwich the macaroons together.