Mix flour, baking powder and salt in a small bowl.
Stir chopped chocolate and margarine in a saucepan over low heat until melted. Remove from heat when melted.
Using electric mixer, beat eggs, sugar, coffee powder and vanilla until well blended. Stir egg mixture into warm chocolate mixture. Stir in dry ingredients. Stir in chocolate chips and chopped walnuts.
Immediately 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.