In the bowl of a stand mixer with a paddle attachment cream softened butter, add powdered milk and mix until well combined. Add flour in two additions, combine until blended. Add California Raisins and blend until incorporated.

Divide batter into 30 g pieces, arrange on parchment paper lined baking trays and using your thumb lightly press a thumbprint into the top. Bake in a preheated oven at 180 ºC for 10-12 minutes or until golden brown. Remove cookies from the oven and while still warm dust with icing sugar.