Preparation
1. Preheat oven to 325°F.
2. Using a stand mixer fitted with the paddle attachment, cream the butter and sugars until fully combined, about 2 minutes. Add the vanilla, mint extract, green food dye and kosher salt to combine.
3. Add the flour and mix on low speed until combined, scraping down the sides of bowl as necessary.
4. Add chocolate and mix on low only to distribute.
5. In the mixer bowl, using your hands, form dough into a ball and scoop the dough ball onto parchment paper. Compress tightly (remember there are no eggs in this recipe to bind) and roll into a log about 3 inches in diameter (should make around two logs).
6. Refrigerate overnight. (In a pinch, pop into the freezer for an hour).
7. Slice log into 1/2-inch rounds. Place 1-inch apart on a parchment paper lined baking sheet and bake in preheated oven for 12-15 minutes (depending on your oven) until the edges begin to brown and tops are no longer translucent. Undercook the cookies a bit so they will be chewy (which may mean less time than the 12-15 minutes).
8. Cool completely on a wire rack.
9. Store at room temperature in an airtight container for 7 days. Dough will keep 7 days in the refrigerator or in the freezer for 1 year.