150g/5½oz jam
300g/10½oz plain flour
3 tsp baking powder
250g/9oz caster or brown sugar
25g/1oz cocoa powder
300g/10½oz icing sugar
50ml/2fl oz sunflower oil
2 tsp vanilla extract
100g/3½oz unsalted butter
50g/1¾oz butter
100ml/3½fl oz double cream
50ml/2fl oz double cream
250ml/9fl oz double cream, whipped until stiff peaks form when the whisk is removed
4 medium free-range eggs
80ml/2½fl oz milk