Preheat oven to 350 degrees F. Butter and flour 12x18x1 inch pan.
In the top of a double boiler,over simmering water, melt 1 pound of chocolate chips with 6 ounces of unsweetened chocolate and butter. Allow to cool slightly.
In a large bowl, stir (do not beat) eggs, coffee granules, vanilla, and sugar together.
Stir the warm chocolate mixture into the egg mixture and cool to room temperature.
In a medium bowl, sift together 1 cup of the flour, baking powder, and salt.
Add to the cooled chocolate mixture.
In a small bowl toss the remaining 1/4 cup of flour with the 12 ounces of chocolate chips and walnuts. (This will help prevent the chips from sinking to the bottom of the pan when baking.)
Add them to the batter.
Pour into the baking pan and spread evenly.
Bake for 20 minutes, then rap the pan against the oven shelf to force the air out from between the pan and dough. Bake for another 15 minutes or until a toothpick comes out clean.
Do not overbake!
Allow to cool thoroughly and cut into squares.