Beat the butter with the sugar, vanilla, and egg until you get a smooth mixture.

Gradually add the flour, baking powder, salt, and ginger, and mix well. Add the walnuts and form a dough ball, then let it rest in the refrigerator for a few hours.

Roll out the dough to a thickness of 1/2 inch and coat each disc with sugar. Place on greased and floured baking sheets.

Preheat the oven to 400°F and bake for 10 minutes or until golden brown.