Ingredients

1/2 cup all-purpose flour
1/4 cup unsweetened cocoa powder
4 teaspoons instant espresso
1 teaspoon baking powder
1/8 teaspoon salt
4 tablespoons unsalted butter
2/3 cup packed light-brown sugar
1 large egg
4 ounces bittersweet or semisweet chocolate, (melted and cooled)
1 tablespoon milk
Confectioners' sugar, for coating

Instructions

In a medium bowl, sift together flour, cocoa, espresso, baking powder, and salt.
With an electric mixer, cream butter and brown sugar until light and fluffy.
Beat in egg until well combined; mix in cooled chocolate.
With mixer on low, gradually add flour mixture.
Beat in milk until just combined.
Flatten dough into a disk; wrap in plastic.
Freeze until firm, about 45 minutes.

Preheat oven to 350 degrees. Line two baking sheets with parchment.
Shape dough into 1-inch balls.
Pour confectioners' sugar (about 1/2 cup) into a medium bowl.
Working in batches, roll balls in sugar two times, letting them sit in sugar between coatings.

Place on prepared baking sheets, 2 inches apart.
Bake until cookies have spread and coating is cracked, (12 to 14 minutes) cookies will still be soft to the touch.
Cool cookies on a wire rack.