Sift together dry ingredients.
In an electric mixer, cream butter and sugar until fluffy.
Add eggs and beat well.
Add dry ingredients, 1 cup at a time, alternating with milk and vanilla beating well after each addition. Wrap and chill dough for at least 1 hour.
Preheat oven to 400.
Butter baking sheets.
Divide dough into 4 pieces.
Roll 1 piece at a time on a floured board to about 1/8 inch thich and cut with large cookie cutters.
Bake for 8-10 minutes.
Do not allow to brown.
Cool on racks.
Mix icing ingredients until smooth.
Spread on cooled cookies and sprinkle with colored sugars, or pipe designs in various colors onto cookies with pastry bag.
Bake at 375º for 8-10 Minutes