2 tbsp custard powder
4–5 tbsp strawberry jam
1 tsp baking powder
200g/7oz caster sugar
150²µ/5½´Ç³ú icing sugar, sifted, plus extra for dusting
200g/7oz self-raising flour
½ tsp vanilla extract
200g/7oz unsalted butter, softened, plus extra for greasing
75g/2½oz unsalted butter, softened
4 large free-range eggs
2 tbsp milk