Preheat the oven at 180 degrees C. Prepare a 8" round cake tin. In a mixing bowl whisk on high speed the egg whites, sugar and cream of tartar until stiff. Leave aside.
In another mixing bowl, whisk all the ingredients A until well mix. Combine beaten ed ingredients A and B.
Pour the batter into prepared tin and bake for 35-40 minutes. Invert immediately and set aside to cool. Slice cake into 3 layers horizontally.
To prepare the yam filling, place all ingredients in a saucepan and cook until slightly thickened, of the fire. Divide the yam paste into 3 portions. Let cool.
To assemble the cake. Place a layer of the cake in a 8" loose-base cake tin and spread a thin layer of yam paste on the cake. Repeat process to the end, finishing with the paste on the top. Leave to set in the refrigerator.
Remove cake from cake tin. Spread sides and top of cake with whipped cream.
