Lemon sour cream cake

1. Preheat oven to moderate, 180°C. Lightly grease and line a 20cm round cake pan.
   
   
2. In a bowl, using an electric mixer, beat butter, sugar and zest together until pale and creamy. Add vanilla, then add eggs one at a time, beating well after each addition. Lightly fold flour into creamed mixture alternately with sour cream and juice, beginning and ending with flour.
   
   
3. Spread mixture into pan. Bake 45-50 minutes until cooked when tested. Cool in pan 5 minutes, before turning onto a wire rack to cool completely.
   
   
4. LEMON ICING: Sift icing sugar into a bowl. Add butter, juice and water. Beat well until smooth and a spreadable consistency.
   
   
5. Spread over cooled cake. Sprinkle with extra zest. Store in an airtight container.

• The cake is cooked if a skewer inserted comes out clean and dry, if the cake springs back after pressing lightly with a fingertip, or if it shrinks from the side of the pan.