Step 1: Heat oven to 180C, whisk together the sugar and butter until smooth. Add the eggs one by one and whisk until runny-ish. Mix in the flour and zest and then pour into a greased container (cake shaped is best).
Step 2: Bake for 35-45 mins and meanwhile make the topping by adding a bit of the lemon juice to the caster sugar at a time until an icing is formed.
Step 3: When cake is cooled pour icing over the top-don’t worry about it running it looks good!