Combine flour, cornstarch, and salt into a medium bowl then whisk to incorporate.

With a hand mixer, cream the room temperature butter, and sugar together.

Mix in vanilla extract, then add the egg to the sugar mixture.

Sift in the dry mixture and mix until almost combined. Scrape the bowl down then mix once more until just combined. Roll the dough into a large rectangle and cut off two smaller sections of dough. Roll the dough back into a ball and cover with plastic wrap and refrigerate it for an hour or two.

For the two smaller sections of dough, use the red food coloring on one and the green food coloring on the other and mix well. Cover the red and green dough with plastic wrap and refrigerate.

Roll the large ball of uncolored dough into a ¼ inch thickness and transfer to a baking sheet. Roll the colored dough out into ⅛ thickness and pinch off little balls of dough. Arrange the colored dough balls onto the uncolored dough. Lightly roll the dough again to press the colored dough into the cookies.

(You don't have to roll the colored dough out, you really just need to make some very small balls of dough and place them over the rolled out dough. )

Place in the refrigerator once again to chill for at least 20 - 30 minutes.

Preheat your oven to 350 F and line your baking trays with parchment paper or silicone baking mats.

Cut out the cookies and place onto your lined baking trays.

Bake for 10 - 15 minutes or until the edges are golden brown.

Remove from the oven and let them cool. Enjoy!