In a large saucepan melt butter and the 1/2 cup chocolate pieces over low heat. Remove from heat. Stir in coffee crystals; cool 5 minutes. Stir in sugars, eggs, and vanilla.
In a medium mixing bowl combine flour, cocoa powder, baking powder, and salt. Stir into coffee mixture. Stir in the 1 cup chocolate pieces. Drop dough by rounded tablespoons onto lightly greased cookie sheets.
Bake in a 350 degree F oven 10 minutes. Let cool 1 minute before removing from sheet. Makes 30 cookies.