Homemade Organic Thin Mint Cookies

Preheat the oven to 350°F. Line 2 cookie sheets with parchment paper.
To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, powdered sugar, and peppermint extract. Mix on low until combined and you don’t see powdered sugar anymore, there will still be a few chunks of butter but that is okay because it’s very soft.
Add the flour and cocoa into the butter mixture and mix on low until combined and smooth. The dough should feel like play dough in your hands.
Using your hands, form the dough into 24 balls and place them on the prepared cookie sheets. Flatten each one slightly so they are about 2-inches in diameter.
Bake for 15 to 18 minutes or until set and dry. Allow to cool completely on the cookie sheets.
To cover the cookies: Using a double boiler, melt about 80% of the dark chocolate until it reaches 115°F on a chocolate thermometer. Remove from heat and add in the remaining 20%, stir vigorously to combine. Allow the chocolate to come down to 91°F.
Using a fork, dip each cookie into the chocolate and pick it up and let the excess chocolate drip off, place back on the parchment paper. Repeat with all the cookies. Place the cookie sheets in the freezer to set the chocolate, for about 10 minutes. Remove from the freezer and using the remaining chocolate, drizzle on top with a spoon (or using a piping bag). Place back in the freezer to set.
Store in the fridge or freezer for up to 1 month.