• Use an electric mixer to beat together the brown sugar, the granulated white sugar and room-temperature butter until the butter is lightly and fluffy (about 2 to 3 minutes)
• Beat in the 4 eggs, one at a time
• Beat in the vanilla extract and peppermint extract
• In a large bowl, whisk together the flour, unsweetened cocoa powder, baking powder and salt.
• Stir the flour mixture and the butter/sugar/egg mixture together until a dough forms.
• Divide the dough into 2 balls, and wrap each ball tightly with plastic wrap. Put the dough in the refrigerator to chill for at least 2 hours.

Bake the Cookies

• Preheat the oven to 350 °F and line 2 large baking sheets with parchment paper.
• Unwrap the Hershey Kisses before you start, so they're ready as soon as the cookies come out of the oven.
• Fill a bowl with sprinkles or sanding sugar for coating the cookies.
• Roll up teaspoon-sized balls of dough and roll each ball of dough around in the sprinkles or sanding sugar to coat.
• Place the cookie dough balls on the baking sheet, with at least 2 inches of space between them (so they don't fuse together when they puff up in the oven.)
• Place the cookies in the oven and bake them for about 6 minutes. They'll look like they're only partly baked when they're ready.
• As soon as the cookies come out of the oven, push a Hershey's Kiss into the center. Let the cookies sit about 5 minutes on the baking sheet before transferring to a cooling rack.