In a large mixing bowl beat butter and cream cheese with an electric mixer on medium speed for 30 seconds. Add powdered sugar, baking powder, and salt. Beat until combined, scraping sides of bowl occasionally. Beat in egg and vanilla. Beat in as much of the flour as you can with the mixer. Stir in any remaining flour

Divide dough into five equal portions; place each portion in an individual bowl. Add desired paste food coloring to four portions, stirring or kneading until dough is evenly colored. Wrap each portion in plastic wrap or waxed paper. Chill dough about 1 hour or until easy to handle.

On a lightly floured surface, roll one portion of the dough at a time until 1/8 inch thick. Cut into 1-inch-wide strips with a fluted pastry wheel; cut dough strips into squares, diamonds, and triangles. Overlap dough pieces in groups of about 10 on an ungreased cookie sheet until the group of pieces is slightly larger than a 3-inch mitten-shaped cookie cutter. With the floured mitten-shaped cutter, cut out dough. (Reserve scraps; reroll to make marble cutouts.)

Bake in a 375 degrees F oven for 8 to 9 minutes or until edges are firm and bottoms are very lightly browned. Transfer cookies to a wire rack and let cool. Makes about 18 cookies.

Layer between waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months.