- Preheat oven to 350 degrees F. Lightly grease a cookie sheet or line sheet with parchment paper; set aside. In a small bowl, combine flour, baking powder, and salt; set aside. In a large bowl, combine eggs, sugar, coffee liqueur, and vanilla. Beat with an electric mixer on medium speed until combined; set aside.
- In a heavy medium saucepan, heat chopped espresso chocolate and butter over medium-low heat until melted and smooth, stirring occasionally. Remove saucepan from heat. Whisk melted chocolate mixture into egg mixture until combined. Stir in flour mixture until just combined. Stir in chopped dark chocolate baking bar.
- Drop dough by heaping teaspoonfuls onto prepared cookie sheet. Bake in the preheated oven for 8 to 9 minutes or until tops appear dry and centers remain soft. Cool on cookie sheet for 3 minutes. Transfer cookies to a wire rack; let cool. Makes about 36 cookies.
From the Test Kitchen
Layer cookies between sheets of waxed paper in an airtight container; cover. Store at room temperature up to 3 days or freeze for up to 3 months.