> 3 cups all-purpose flour, plus more for dusting
> 1 tsp baking powder
> 1/2 tsp salt
> 1 cup (2 sticks) unsalted butter, softened
> 1 cup sugar
> 1 large egg
> 2 tsp vanilla extract
> Red and green food coloring
In a medium bowl, whisk together the flour, baking powder, and salt. In a large bowl, using a hand mixer or stand mixer, beat the butter and sugar 2–3 min., until smooth and creamy. Mix in the egg and vanilla. In batches, gradually beat in flour mixture.
Remove half of dough from mixing bowl and set aside. To dough in mixing bowl, add about ¼ tsp green food coloring. Mix just until uniform in color. Transfer to a sheet of plastic wrap and form into a disk. Wrap tightly and refrigerate.
Wash beaters and mixing bowl. Add remaining dough and about ¾ tsp red food coloring. Mix just until uniform in color. Transfer to another sheet of plastic wrap and form into a disk. Wrap tightly and refrigerate. Chill both pieces of dough 2 hours, until firm.
On a lightly floured work surface, break off walnut-size chunks of green dough and scatter evenly. Break off walnut-size chunks of red dough and scatter in between the green dough chunks. Top with a large sheet of wax or parchment paper. With rolling pin, roll to ⅛-inch thickness. Remove paper and, with cookie cutters, cut out shapes. Arrange on a large parchment-lined cookie sheet, spacing 1 inch apart. Chill 30 min. Preheat oven to 350°F.
Meanwhile, continue scattering, rolling, and cutting out cookies from remaining dough (carefully reroll dough only 1 time, taking care not to overmix the colors). Bake each sheet of cookies 8–10 min., until edges are set. Cool completely on wire rack. To store, keep in a sealed container at room temperature for up to 1 week.