In a large bowl, use an electric mixer to beat together butter and granulated sugar.

Once butter and sugar are well combined, add eggs and vanilla and mix some more.

Next, add flour, baking powder and salt. Mix until cookie dough forms.

Divide the cookie dough into two equal halves. Color one half with red gel food coloring and the other with green gel food coloring. Knead each dough half until they’re both completely tinted.

Sprinkle a working surface with flour. As well, add flour onto a rolling pin.

Begin by rolling out the green cookie dough into a rectangular shape, until it’s slightly larger than 6 in x 9 in. Set aside.

Do the same for the red cookie dough and press it on top of the green cookie dough.

With a paring knife, trim the cookie dough so that it’s exactly a rectangular shape, 6 in x 9 in.

Rolling lengthwise (so from the thinner end), roll the layered cookie dough into a log.

Wrap it in plastic and refrigerate for one hour.

Remove the cookie log from the fridge once time is up. Preheat oven to 375 degrees F and line a cookie sheet with parchment paper.

Cut out 12 cookie slices from the log, about ½ an inch thick. Line them up on the lined baking sheet.