Mix flour, baking powder and salt in a small bowl. Set aside.
Stir chopped chocolate and margarine in a saucepan over low heat until melted. Remove from heat when melted.
Using an electric mixer, beat eggs, sugar, coffee and vanilla until well blended. Stir into warm chocolate mixture. Stir in dry ingredients. Add chocolate chips and walnuts.
Drop dough by tablespoonful onto a non-stick baking sheet, 1-1/2 inches apart. Bake for about 12 minutes or until tops crack. Cool cookies on tray for 5 minutes. Transfer cookies to cooling rack and cool.