in oven until toasted, 10 to 12 minutes or until they develop a toasty aroma. Remove from oven and set aside to cool. Increase oven temperature to 350 degrees. Place unsweetened chocolate, 12 oz semi-sweet chocolate, butter, margarine and espresso in top of double boiler and place over simmering (not boiling) water until chocolate is about 3/4 melted. Meanwhile, beat the eggs with a wire whisk in a large mixing bowl. Gradually add sugar, whisking until mixture becomes thick and light in color. When chocolate is almost melted, remove from heat and stir until completely melted and satiny in appearance. Gradually whisk chocolate into egg mixture. Stir with a wooden spoon to incorporate. Sift flour, baking powder and salt directly into chocolate mixture. Gently stir until the dry ingredients are barely incorporated. Cut the 6 oz of semi-sweet chocolate into 1/2 inch chunks and stir into dough along with the toasted nuts. Lightly butter 4 aluminum baking sheets. (do not use foil or cookies will burn) Drop dough by tablespoonfuls, 12 to a sheet to leave room for cookies to spread. Bake only one sheet at a time in center of oven. Bake at 350 degrees for 10 to 12 minutes, or until cookies lose their shine. Cookies will still be very soft. Allow to cool for 2 minutes before removing from pans. Using a pin-sized tip on an icing bag, pipe melted semi-sweet chocolate onto cookies in a criss-cross pattern. Allow to cool at least 1 hour before storing in tins. Makes 50 one-ounce cookies