Helene's Pesach Sponge Cake

Mum is rubbish at making sponge cakess (by her own admission!), but this is the only sponge cake that my dad, Harry will eat, so it must be good.

This is enough to make 2 cakes

1. 1

   Preheat oven to 170C. grease & line 2 15cm cake tins
   
   Separate the eggs and beats the eggs together with the sugar.
   
   Add the cake meal and potato flour.
   
   Beat the egg whites till stiff peaks and fold in to the batter.
   
   Pour into the cake tins & bake for 1 hour.
   
   When removed from oven turn upside down so the bottom sinks, not the top!