- 225 g unsalted butter very soft, plus extra for greasing
- 225 g caster sugar
- 4 large eggs at room temperature
- 225 g self-raising flour
- 1 tsp baking powder
- 1 tsp vanilla extract
- 4 tbsp good-quality strawberry or raspberry jam
- 150 g butter and 250g icing sugar for the buttercream, or 200ml whipped double cream
- Caster sugar for dusting