For the jam
450g/1lb strawberries, chopped
300g/10½oz jam sugar
For the sponge
225g/8oz self-raising flour
4 free-range eggs
225g/8oz caster sugar
225g/8oz margarine
vanilla extract
For the buttercream
250g/9oz icing sugar, plus extra for dusting
65g/2¼oz butter
1 tbsp milk
Method
Preheat the oven to 190C/375F/Gas 5. Line two Swiss roll tins with greaseproof paper.
For the jam, place the strawberries and sugar in a heavy-based saucepan, bring to a boil and cook for 10 minutes. Transfer to a bowl and set aside to cool…
