01 -
Put the butter and sugar in the mixing bowl of a stand mixer. Use the paddle attachment and beat on medium speed for 3-4 minutes until smooth. Toss in the egg and vanilla, then mix thoroughly.
02 -
In a separate bowl, stir together the flour, baking soda, and salt. Lower the mixer’s speed and slowly add the dry mix until it’s all blended.
03 -
Split the dough into three portions. Tint one part red, another green, and leave the last portion natural. Roll each into a ball, wrap with plastic, and chill for an hour.
04 -
Press each chilled ball between sheets of parchment into a square roughly 7 inches wide. Chill again for 15 minutes.
05 -
Layer the dough sheets one on top of the other in this order: red, green, then plain. Flatten them into a 12x8-inch rectangle. Roll tightly from the long side into a log. Wrap with parchment and freeze for about 60 minutes.
06 -
Turn on the oven to 350°F. Put parchment paper on your baking trays.
07 -
Cut the chilled dough log into slices about 1/3-inch thick with a serrated knife. Coat the edges with red sanding sugar. Space them about an inch apart on the prepared trays.
08 -
Pop them in the oven for 8-10 minutes until firm. Let them sit on the tray for 1 minute before moving to a cooling rack.