Homemade Thin Mints

For the cookies:

(8 oz, or 2 sticks) unsalted butter, at room temperature

unsweetened cocoa powder (I used Dutched dark cocoa powder which worked well)

powdered sugar

vanilla

salt

all purpose flour (fluff the flour before scooping and leveling the cup, too much flour will result in a dry dough)

For the coating:

semi-sweet baking chocolate

vegetable or coconut oil

Approximately 1 teaspoon peppermint extract or oil (Make sure you get peppermint, not spearmint, and make sure you get extract, or oil, not flavoring) I used McCormick's Pure Peppermint Extract