Shortbread Checkerboard Cookies

• Please note that this recipe has a LOT of chill time (but I promise it's worth it!), so be sure to plan accordingly. Use an electric mixer to combine 2 cups of butter, 4 cups of flour, 1 cup of powdered sugar, and 1 tsp of fine salt. The mixture might look a bit crumbly at first, but it will eventually form a soft dough once it's fully mixed. If the mixture isn't coming together, you may want to heat it in the microwave for a couple of seconds (literally 2-3 seconds, you don't want to melt the butter!) to help soften the butter.
• Scoop a third of the uncolored dough (about 370g) onto a large piece of plastic wrap and spread it out to be 1/2 inch thick (rolling pin rings or even two pieces of wood to act as a guide help a ton), and 5 inches or 13cm wide. It's important that all three doughs are close in size and thickness, so that you minimize any bits you have to trim off and so that the pattern ends up symmetrical. Wrap the dough tightly and place it in the fridge to chill.
• Divide the remaining dough in half (370g each) and use gel food coloring to color one portion red and the other green. Repeat the step above to spread the dough out and wrap it before placing it in the fridge. Let all three portions of dough chill for at least an hour, or overnight.
• Remove one portion of dough from the fridge at a time and unwrap it so that it's sitting on top of the plastic wrap (this keeps your counters clean and makes the dough easy to move later). Then place the plastic loosely over the top (this prevents the dough from sticking to the rolling pin) and roll it out again to make sure it's exactly 1/2 inch thick. It's super helpful to use rolling pin rings or some type of guide to make sure the dough is the right thickness.
• Use a ruler to mark a rectangle that is 4.5 inches or 11.5cm wide on shorter sides into the dough, then cut off the edges to create crisp lines (see pictures above).
• Use a sharp knife to cut 9 long strips of dough that are the exact same width (1/2 inch) as they are in height. And yes, I HIGHLY recommend using a ruler as you do this! Once you've cut one color, lift the plastic wrap up and move it back to the fridge. The colder the dough is when we stack it, the easier it will be to work with! Repeat this process with all the portions of dough.
• Then preheat the oven to 350°F/175C° and line two large, light colored (aluminum is best) baking sheets with silicone mats or parchment paper. Then get out a large cutting board and a sharp chef's knife.
• Remove the dough strips from the fridge and begin to assemble the cookies on the cutting board. Keep in mind that you will be making about 3 logs of checkboard dough, so try to space them accordingly so you can easily cut them later. I built mine in this order: 1st layer (white, green, red), 2nd layer (red, white, green), 3rd layer (green, red, white).
• Once they're all stacked, use the flat edge of a large knife or a bench scraper to gently press down on the dough to help all the pieces stick to each other. As long as the dough is still cold and firm, gently flip it over and press down on all four sides. Repeat this process with all 3 logs of dough.
• If you are able to work quickly and the dough is still cold and firm, you can cut it immediately. If you notice the dough softening up, place the cutting board in the fridge for another 30 minutes, or in the freezer for 15 minutes. You want the dough to be firm so that when you cut in, you don't squish the dough and ruin that perfect pattern.
• When you are ready to cut them, use a sharp knife to cut slices that are about 1/3 inch thick. The cookies will spread a bit as they bake, so place the cookies about 2 inches apart on the prepared baking sheets. Bake them one tray at a time for 12-14 minutes, or just before the edges start to brown. I highly recommend rotating the pan halfway through to help them bake more evenly.
• Then remove the cookies from the oven and let them cool fully on the pan and enjoy!