425g tin pineapple rings in juice (drained weight 250g)
1 tsp baking powder
4 tbsp soft light brown sugar
175g/6oz caster sugar
pinch of salt
175g/6oz self-raising flour
Β½ tsp vanilla bean paste
235g/8oz unsalted butter, softened, plus extra for greasing
3 free-range eggs, beaten
2 tbsp milk