Preheat oven to 350°F Grease and flour a 13 by 18 by 1 ½-inch sheet pan.
Melt together the 1 Pound Unsalted Butter or the Substitute, 16 Ounces Chocolate Chips, and 6 Ounces Milk or Dark Chocolate on top of a double boiler. Let it cool slightly. Stir together the eggs, instant coffee, vanilla and sugars. Stir in the warm chocolate mixture and cool to room temperature.
Sift and Stir together the Flour, Baking Powder and Salt. Add to cooled chocolate mixture. Toss the walnuts and 12 ounces of Chocolate Chips with ¼ cup flour to coat. Then fold the walnuts and Chocolate chips it into the chocolate mixture. Pour into prepared pan.
Bake for about 30 minutes, or until tester just comes out clean. Halfway through the baking, rap the pan against the oven shelf to allow air to escape from between the pan and the brownie dough. Do not over-bake! Cool thoroughly, refrigerate well and cut into squares.