In medium saucepan, combine bittersweet chocolate, unsweetened chocolate, and butter; heat and stir over low heat until mixture is melted and smooth. Remove from heat and cool for about 10 minutes.

In large bowl, combine sugar, eggs, and coffee; beat with electric mixer on medium to high speed for 2 or 3 minutes or until well mixed and color becomes slightly lighter. Add cooled melted chocolate, beating until combined. In a small bowl, stir together flour, baking powder, and salt. Add to chocolate mixture; beat until combined. Stir in chocolate pieces. At this point, the dough will look like brownie batter.

Cover dough with wax paper and let stand at room temperature for 20 minutes so that dough can thicken.

Preheat oven to 350°F

Line cookie sheets with parchment paper, silicone, or foil. Scoop 3 ounces of dough per cookie (use 3 tablespoons of dough if you do not have a 3 oz scoop) in mounds 2 inches apart on cookie sheets.

Bake in preheated oven about 13 minutes, or until tops are set and the cracks on top do not appear moist. Do not attempt to cook these in a cold oven - they do not turn out well. Let cookies cool on cookie sheet for one minute before transferring to a wire rack to cool.