Preheat oven to 350.
Butter and flour a 12x18x1 inch baking sheet
Melt butter, 1 pound of chocolate chips and the unsweetened chocolate in a bowl over simmering water.
Set aside to cool.
In a large bowl, mix eggs, sugar, coffee, vanilla. Do not beat. Set aside.
Stir slightly cooled chocolate into egg/sugar mixture, cool to room temperature.
In medium bowl, sift salt,flour and baking powder.
Add flour mixture to cooling chocolate mixture. Pour into baking sheet.
Bake 20 minutes, then tap pan on oven rack to release air bubbles. Bake another 15 minutes, test with a toothpick to see if it comes out clean, do not over bake. Allow to cool.
