Combine butter and sugar in bowl of electric mixer and beat until smooth. Beat in eggs.
Sift together flour, cinnamon, coriander, anise, baking powder, ground fennel, ground ginger, cloves, salt, and mace into a separate large bowl.
With mixer on low, slowly add dry ingredients to butter mixture until dough holds together.
Remove dough from bowl and wrap in plastic wrap. Refrigerate until firm, approximately 2 to 4 hours.
Preheat oven to 350ºF and grease 2 cookie sheets.
Remove dough from refrigerator and set aside at room temperature for approximately 10 minutes. Divide dough in half, place half onto a floured surface. Roll dough to 1/8-inch thickness, flouring surface and rolling pin as needed.
Cut out cookies with cookie cutters (dip cutters in flour for a clean edge). Transfer to baking sheets 1 inch apart.
Lightly brush cookies with milk and sprinkle with colored sugar.
Bake until firm and edges begin to darken, approximately 10 to 14 minutes. Allow cookies to slightly cool on cookie sheet, the transfer to wire racks to completely cool. Repeat with remaining dough.
Makes approx. 3 dozen cookies.