1 1/2 c. flour
1/2 c. powdered sugar, plus more for dusting
1/2 c. cornstarch
1 tsp. salt
2 sticks margarine, room temperature
2 Tbs. key lime juice
In an electric mixer, beat the margarine for 1-2 minutes until slightly fluffy. Add all of the dry ingredients, slowly incorporating. Add the key lime juice and mix until just combined. Dust your work surface with powdered sugar. Divide the dough in half, and roll each half into a 10 inch log. Wrap tightly in Saran Wrap and stick in the freezer for at least 2 hours until the dough is firm.
Line a cookie sheet with parchment paper. Remove the dough from the freezer and cut into 1/4 inch slices (you may need to re-configure some of them if they get flattened while cutting, so that you have more of a circular shape). Place on the parchment paper and make a finger indent in the very center of each cookie. Bake in a preheated 350 degree oven for 8-10 minutes. Let cool fully on a wire rack.
When the cookies are fully cool, spoon the key lime glaze on top, which consists of 3/4 c. powdered sugar and 1 1/2 Tbs. key lime juice. Add green edible glitter if you want to give them more of a shine! *If you are packaging these cookies by overlapping them or stacking, make sure you wait until the glaze hardens, at least 30 minutes after spooning onto the cookies.