In a bowl, stir together flour and baking powder. In another bowl, beat butter with sugar until fluffy and light. Beat in eggs and vanilla. Stir in flour mixture, a third at a time to make a stiff dough. Divide dough into 4 pieces. Roll out a portion of cookie dough to 1/4 inch thick. Cut out shapes using cookie cutters. Place on lightly greased or nonstick cookie sheets. Bake until lightly golden, about 10 minute, rotating baking sheet halfway through cooking time. Cool completely on pans about 5 minutes, transfer to cooling racks and cool completely before decorating.
In a small bowl, mix sugar and water to form a thick, smooth icing. Stir in food coloring to reach desired shade. Drop icing onto cookies using a small teaspoon and smooth with the back of the spoon. Make additional bowls for additional colors.
Additional multi-colored sprinkles can be added on top of icing before it dries for more decorative cookies, if desired.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.