Method

• 01
  In the bowl of a stand mixer (or use a hand mixer) cream the butter and sugar together until light and fluffy.
• 02
  Add the egg and vanilla and beat again until very smooth.
• 03
  In another bowl combine the flour, baking powder and salt.
• 04
  Slowly add the flour mixture to the batter and mix until the dough comes together.
• 05
  Divide the dough into three equal pieces.
• 06
  Add one piece of dough back into the mixer and add a drop of red color mixing on low speed until the dough has turned red.
• 07
  Repeat the process with another piece of dough except adding a drop of blue color.
• 08
  You should now have one piece of red dough, blue dough, and regular uncolored dough.
• 09
  Roughly flatten out each piece of dough to about 6 inches long and then stack them on top of one another.
• 10
  Roll the dough into a sausage shape about 8 inches long and 2 inches wide making sure it's nice and even.
• 11
  Lay the roll of cookie dough on a piece of wax paper and wrap up tightly like a tube.
• 12
  Let the dough rest in the fridge overnight or at least 6 hours to firm up.
• 13
  Preheat the oven to 400℉ and line a couple of baking sheets with parchment paper.
• 14
  Unwrap the roll of cookie dough and slice into discs about 1/4 inch thick.
• 15
  Lay each cookie onto the prepared pans and bake for 8-10 minutes depending on your oven, the edges and bottoms should be a light golden color.
• 16
  Transfer the baked cookies to a wire rack to cool and repeat until all the cookies have been baked.