Combine all ingredients in a stand mixer with paddle attachment and mix at low speed until all ingredients are fully combined. Mixture will be crumbly.
Using your hands press the dough into a rough log shape and place on a sheet of plastic wrap. Wrap plastic around the dough log then continue to form it into a smoother log shape of the diameter you want your cookies to be.
Refrigerate dough for 30 minutes. During last 10 minutes of chill time preheat oven to 350 degrees and line a cookie sheet with parchment paper.
Place shortbread log on cutting board and slice into 1/4 inch disks and place them on the the cookie sheet. Bake for 9 to 11 minutes. Allow to cool on cookie sheet for 5 minutes before transferring to a wire cooling rack.
When cookies are cool place them on a sheet of wax paper about 1/4 inch apart. Melt chocolate and spoon it into a resealable plastic bag then prick the corner with a toothpick. Drizzle chocolate over cookies and let them sit for about an hour for the chocolate to harden.