Preparation time: 20 minutes
Total cooking time: 15-20 minutes
Makes one 20cm cake

1. Preheat oven to moderate 180°C. Brush 2 shallow 20cm round cake tins with melted butter or oil. Line bases with paper; grease paper. Dust tins lightly with flour, shake off excess. Sift combined flours 3 times onto greaseproof paper.
   
   
   
   
2. Using electric beaters, beat eggs and lemon rind in a small bowl for 5 minutes or until thick and pale. Add sugar gradually, beating constantly until mixture is pale yellow and glossy. Transfer mixture to large bowl. Using a metal spoon, fold in flours quickly and lightly. Spread mixture evenly in prepared tins. Bake for 15 minutes or until sponges are lightly golden and shrink from sides of tins. Leave sponges in tins for 2 minutes before turning onto a wire rack to cool.
   
   
   
   
3. Using electric beaters, beat cream in medium mixing bowl until stiff peaks form. Spread cream evenly over 1 sponge layer. Place remaining sponge on top.
   
   
   
   
4. To make Passionfruit Icing: Combine icing sugar, butter and pulp in heatproof bowl. Stand bowl in pan of simmering water and stir until icing is smooth and glossy; remove from heat. Spread icing over top of sponge using a flat-bladed knife.
   

Hint: When you are making sponge cakes, it is important to gently fold the flour into egg mixture. If you try to beat the flour in, the texture will become thick and heavy.