- Melt chocolate chips and butter in top of double boiler over boiling water and medium-low heat, stirring to blend.
- Stir in brown sugar, vanilla and coffee.
- Remove from heat, and set aside.
- Whisk together flour, cocoa, baking powder and salt.
- Using an electric mixer on high speed, beat whole egg, egg whites and granulated sugar until light and thick, for about 3 minutes.
- Reduce speed to low, and slowly add melted chocolate mixture.
- Beat in flour/cocoa mixture.
- Transfer to a smaller bowl, cover and refrigerate for about 3 hours.
- Preheat oven to 350°F.
- Lightly spray cookie sheets with nonstick cooking spray.
- Scoop heaping tablespoons of dough onto cookie sheet, placing them about 2 inches apart.
- Bake for about 15 minutes, or until center of cookie sets.
- Remove from oven, and cool on wire racks.