1. Beat egg whites untill stiff. Add sugar and beat until peaks form.
2. Reduce speed, add yolks, flour, walnuts and baking powder.
3. Fold in grated chocolate by hand.
4. Pour into lined cookie sheet. Bake at 350 degrees Fahrenheit for 20 to 25 minutes.
5. Invert onto dish towel dusted with confectioners sugar. Roll up while still warm.
6. When cool, unroll and frost with desired frosting and roll up.