- 1/2 cup (1 stick) unsalted butter, room temperature
- 1/4 cup powdered sugar
- 1/2 teaspoon vanilla extract
- 1 1/4 cups all purpose flour
- 1/4 teaspoon salt
- 9 ounces good-quality white chocolate (such as Lindt or Baker's)
- Blue, red and green food coloring
- 2 small resealable plastic bags
- Preheat oven to 325&;deg;F. Using electric mixer, beat unsalted butter in large bowl until light. Gradually beat in powdered sugar. Beat in vanilla extract. Add flour and salt and mix just until combined. Gather dough into ball; flatten into disk. Wrap disk in plastic and refrigerate until firm, about 3 hours.
- Roll out dough on floured work surface to 1/8-inch thickness, frequently lifting and turning dough to prevent sticking. Using 5-inch Christmas tree cookie cutter, cut out cookies. Gather dough scraps together. Repeat rolling and cutting dough scraps to make 10 cookies total. Transfer cookies to 2 heavy large baking sheets, spacing apart. Bake until cookies begin to brown around edges, about 15 minutes. Cool on baking sheet 5 minutes. Transfer cookies to racks and cool completely.
- Melt chocolate in top of double boiler over simmering water, stirring until smooth. Divide melted chocolate among 3 small bowls. Working quickly so that chocolate does not harden, mix 8 drops blue food coloring into 1 bowl. Spread blue chocolate evenly over surface of cookies. Mix 8 drops green food coloring into second bowl of melted chocolate. Mix 8 drops red food coloring into third bowl of melted chocolate. Spoon green chocolate into plastic bag. Cut off 1 bottom tip of bag to allow small ribbon of chocolate to come out. Repeat procedure with pink chocolate and another plastic bag.
- Using green chocolate, pipe 4 diagonal lines from left to right across cookies, spacing evenly. Using pink chocolate, pipe 4 diagonal lines from left to right across cookies, alongside green lines. Repeat with diagonal lines going from right to left. Let cookies stand until chocolate sets, about 2 hours. (Can be prepared 3 days ahead. Store cookies between sheets of waxed paper in airtight container at room temperature.)