blue food colouring
6 tbsp good-quality strawberry jam
175g/6oz caster sugar
300驳/10陆 icing sugar
2-3 tbsp icing sugar, for dusting
500g/1lb 2oz white, ready-made marzipan
175g/6oz self-raising flour
陆 tsp vanilla extract
175g/6oz softened butter, plus extra for greasing
150驳/5录辞锄 butter, softened
3 free-range eggs