Beat butter in a large bowl with an electric mixer on medium to high speed for 30 seconds. Add sugar, baking powder, and salt. Beat until combined, scraping side of bowl occasionally. Beat in egg and vanilla until combined. Beat in as much flour as you can with the mixer. Stir in any remaining flour. Divide dough in half. Cover and chill dough in the refrigerator for 1 to 3 hours or until easy to handle.

Preheat oven to 375F. Roll each half of the dough to 1/8-inch thickness, on a lightly floured surface. Cut dough with a floured 3-1/2-inch mitten-shaped cookie cutter. Place cutouts 2 inches apart on ungreased cookie sheets.

Bake in preheated oven about 8 minutes or until edges are set. Transfer cookies to wire racks and let cool. If desired, spread with Powdered Sugar Icing. Let stand until slightly set; pipe icing in decorative designs over iced cookies. Let stand until icing is set. Makes 36 cookies.

Powdered Sugar Icing: Stir together 3 cups powdered sugar, 2 to 3 tablespoons milk, and 1 teaspoon vanilla in a medium bowl to make of piping or spreading consistency. Divide icing and tint portions with desired food coloring. Makes about 2 cups.

To store: Place uniced cookies in layers separated by pieces of waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months. Thaw cookies, if frozen. If desired, spread and/or pipe icing on cookies.