8 oz bitterweet chocolate, finely chopped
1 1/4 cups all purpose flour
1/2 cup unsweetened dutch-process cocoa powder
2 teaspoons baking powder
1/4 teaspoon coarse salt
1/2 cup (1 stick) unsalted butter, softened
1 1/2 cup packed light-brown sugar
2 large eggs
1 teaspoon pure vanilla extract
1/3 cup whole milk
1 cup granulated sugar
1 cup confectioners’ sugar
1. preheat oven at 350F. melt chocolate in a heatproof bowl set over a pan of simmering water, stirring. Set aside and let cool. Sift together flour, cocoa powder, baking posder and salt in a medium bowl; set aside
2. mix butter and brown sugar on medium speed until pale and fluffy, 2 to 3 mins. mix in eggs and vanilla, and then the melted chocolate. Reduce speed to low; mix in flour mixture in 2 batches, alternating with the milk. Divide dough into 4 equal pieces. Wrap each in plastic; refrigerate until firm, about 2 hours
3. Divide each piece into 16(1-inch) balls. Roll in granulated sugar to coat, then in confectioners’ sugar to coat. Space 2 inches apart on baking sheets lined with parchment paper.
4. Bake until surfaces crack, about 14 min. Let cool on sheets on wire racks. Cookies can be stored between layers parchment in airtight containers up to 3 days