How to Make It
Beat butter, sugar, and salt at medium speed with a heavy-duty electric stand mixer until creamy. Add vanilla; beat until well blended. Gradually add flour, beating at low speed until blended. (Dough will be very soft.)
Divide dough into 2 equal portions; wrap each with plastic wrap, and flatten into a disc. Chill 2 to 24 hours.
Preheat oven to 350°. Unwrap 1 dough disc on a well-floured surface. Cover with a large piece of plastic wrap, and roll to 1/4-inch thickness; cut into desired shapes with 3 1/2-inch cookie cutters. Place 1 inch apart on ungreased baking sheets. Chill 15 minutes. Repeat procedure with remaining dough disc.
Bake at 350° for 14 to 17 minutes or just until edges are lightly browned. Cool on baking sheets 5 minutes. Transfer to wire racks, and let cool completely (about 30 minutes). Decorate cookies with icing. Let stand 1 hour or until icing is firm.
Icing: Whisk together first 3 ingredients and 6 to 8 Tbsp. water until smooth. Divide mixture into 5 to 6 small bowls; tint icing in each bowl with desired food coloring paste or drops, stirring until blended.
For testing purposes only, we used Wilton Meringue Powder. Meringue powder and food coloring paste can be found at crafts and cake-decorating stores.