Stir the eggs into the mixture one by one. Butter a 22cm mould with high sides, sprinkle in some sugar, and then pour in the mixture. Place the mould in a large saucepan into which you have added water so that it comes half way up the sides of the mould. When the water starts to boil, cover the mould with a small lid and lower the heat until it’s just simmering. Cook the cake for 45-60 minutes then do the toothpick test – it should come out clean.