Stir together the
flour, baking powder, and mace in a medium bowl. Beat the butter, sugar, and vanilla in a large bowl
with an electric mixer at high speed until pale and
creamy.
With mixer at medium speed, add the eggs,
one at a time, and beat until just combined. With
mixer at low speed, gradually beat in the mixed dry
ingredients.
Wrap in plastic wrap and refrigerate
for at least 2 hours. Preheat oven to 350°F/180°C/gas 4. Grease and lightly flour a baking
sheet.
Roll out the dough on a lightly floured
work surface to 1/8 inch (3-mm) thick. Cut with
cookie cutters in round or other shapes.
Carefully
transfer the cookies to the prepared trays. Bake
for 10-12 minutes, or until golden. Transfer to
racks to cool.
Mix the confectioners' sugar with
the water and spread over the cookies.