01 -
Preheat oven to 350°F (177°C). Line a baking sheet with parchment paper or a silicone baking mat, then set aside.
02 -
Using a stand mixer fitted with a paddle attachment, cream the softened butter with granulated and brown sugars until the mixture is light and creamy.
03 -
Add egg white and vanilla extract to the creamed butter mixture and mix for 30 seconds until fully combined.
04 -
Gradually mix in the flour, baking soda, baking powder, and salt just until incorporated and no flour streaks remain.
05 -
Divide the dough evenly into three portions. Leave one portion plain, tint one with red gel food coloring, and one with green gel food coloring.
06 -
Scoop one teaspoon of dough from each colored portion. Either gently press the three colors together to form a simple marbled pattern or split each teaspoon in two and randomly layer them before rolling to create an elaborate design.
07 -
Place shaped dough balls on the prepared baking sheet spaced apart. Bake at 350°F (177°C) for 7 minutes.
08 -
Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving.