Preheat oven to 325°F. Mix flour, salt, cinnamon and nutmeg in medium bowl. Set aside. Beat butter and sugar in large bowl with electric mixer on medium speed until light and fluffy. Add egg and vanilla; mix well. Gradually beat in flour mixture on low speed until well mixed.
Roll out dough on generously floured surface to 1/4-inch thickness. Cut into shapes with your favorite holiday cookie cutters. Place on ungreased baking sheets.
Bake 8 to 10 minutes or until edges start to brown lightly. Cool on baking sheets 1 minute. Remove to wire racks; cool completely.
For the Icing, mix confectioners' sugar and milk with wire whisk until well blended and smooth. (Stir in additional milk, 1 teaspoon at a time, until desired consistency is reached.) (Makes 1 cup.) See tips below to make holiday icing colors.
To ice cookies, hold cookie by its edge and dip top of cookie into icing. (Or spoon the icing onto cookie using a teaspoon.) Place iced cookies on wire rack set over foil-covered baking sheet to dry. (The foil-covered baking sheet will catch drips.) To add decorative details to cookies, spoon tinted icing into resealable plastic bag. Snip off a tiny piece of the corner. Squeeze icing through hole in plastic bag to decorate cookies. If desired, Colored Sugar may be sprinkled onto freshly iced cookies.
Each color combination below is enough to tint 1 cup icing.
• RED: Mix 1 teaspoon Red, 30 drops NEON Pink, 10 drops Yellow and 2 drops Blue into 1 batch of frosting.
• BROWN: Mix 6 drops Black, 25 drops Yellow and 18 drops NEON Purple into 1 batch of frosting.
• BLUE: Mix 4 drops NEON Pink and 8 drops NEON Blue into 1 batch of frosting.
• YELLOW: Mix 16 drops Yellow and 1 drop Red into 1 batch of frosting.
• BLUE: Mix 2 drops NEON Blue and 1 drop NEON Pink into 1 batch of frosting.
• GREEN: Mix 35 drops Green and 1 drop Black into 1 batch of frosting.