Cream together margarine and sugar until light and fluffy. Add vanilla and sugar substitute to creamed mixture and mix lightly. Stir together flour, cocoa, coffee and baking powder to blend. Add to creamed mixture and mix at meidum speed 1-2 minutes or until blended. Add raisins and nuts to dough and mix lightly. Add egg whites to dough and mix until egg white are adsorbed into the dough. Drop dough by tablespoonsful onto a cookie sheet that has been lines with alumium foil or sprayed with PAM. Using your fingers dipping in cold water, shape dough into round cookies about 1 cm thick. Spread the dough carefully because the finished cookie will be the shape of the dough after it is baked. Bake at 190ºC for about dozen minutes, or until the dough springs bnack when touched. Transfer from the hot cookie sheet onto a wire rack and cool to room temeprature.
Serve one cookie per serving.