Method

• Step 1
  Heat oven to 180C/160C fan/gas 4, butter and line the base of two 20cm spring-form cake tins with baking parchment.

• Step 2
  Using an electric whisk beat the butter and sugar together until pale and fluffy. Crack the eggs in one at a time and whisk well, scraping down the sides of the bowl after each addition. Add the lemon zest, vanilla, flour, milk and a pinch of salt. Whisk until just combined then divide the mixture between the two tins.

• Step 3
  Bake in the centre of the oven for 25-30 mins until a skewer inserted into the middle of each cake comes out clean. After 10 mins remove the cakes from their tins and leave to cool completely on a wire rack. Fill how you like. Will keep for 3 days.