Cookies:

1. Combine flour, powdered sugar, salt and cornstarch in a bowl, set aside.
2. Beat butter until smooth. Slowly add in dry ingredients and key lime juice. Mix until dough just comes together.
3. Divide dough in half and shape each half into 10 inch logs.
4. Wrap them in cling wrap and chill for at least 2 hours.
5. When ready to bake, preheat oven to 350° and line baking sheet with parchment paper.
6. Remove dough from fridge and cut into 1/4″ slices with a sharp knife.
7. Bake for 9-10 minutes until cookies are set and edges just start to brown.
8. Cool on a wire rack completely before glazing.

For glaze:

1. Combine powdered sugar, lime zest and lime juice in a medium bowl and stir until smooth.
2. Spoon a teaspoon of glaze on each cookie and gently spread around until cookie is coated.
3. Let glaze set, approx 30 minutes.