From Beyond Frosting
1 cup salted butter, at room temperature
1 cup granulated sugar
1 teaspoon baking soda
4 tablespoons milk
2 teaspoons vanilla extract
2 large eggs
½ teaspoon salt
5 cups all-purpose flour
Gel colors for dying
Beat the butter and sugar on medium-high speed until the sugar is dissolved and creamy. Add the eggs and flavored extract to the butter and beat until all ingredients are well incorporated. Then, in a small glass dish, dissolve the baking soda in the milk and add to the mixture, beating until combined. Finally, add the salt and the flour 1 cup at a time and mix until a stiff dough forms.
Divide the dough into 6 equal sized balls. Dye each one the individual color using either your mixer or your hands.
Starting with the red, roll each individual color into a rectangular shape, about 12 inches long and 3-4 inches wide. (Roll between two pieces of parchment paper and lightly dust with powdered sugar if needed to prevent sticking.) Dough will be relatively thin when rolled, place the first one on piece of parchment paper and stack each colorful rectangle on top of the other.
Once all the colors are stacked, cover with a second piece of parchment paper and proceed with roll out the cookie dough again until it’s about ¼ – ½ inch thick, it should expand quite a bit.
Trim off the excess sides and then cut the dough into two halves. Roll each one tightly into a log, about 9-10 inches long and about 2-inch in diameter at the thickest point. Wrap each log with plastic wrap and place seam side down and chill for at least 30 minutes.
Pre-heat oven to 350°F. Line a baking sheet with a silicone baking mat or parchment.
Remove the dough from the fridge. Using a sharp knife, cut them into ½ inch wide slices. If they are misshaped, gently roll between your hands to shape into a circle. Place about 1-inch apart on the baking sheet.