75g (3oz) soft butter
75g (3oz) caster sugar
100g (4oz) self-raising flour
1 tsp baking powder
2 large eggs
zest of 1 orange
900g (2lb) plums, cut in half, stones removed
About 150g (5oz) Demerara sugar
Pre heat oven to 200C or for two door aga bake on grid shelf on the floor of the roasting oven.
Generously butter a 28cm (11in) about 4cm (1½in) ovenproof dish or deep loose-bottomed flan tin.
Measure the first six ingredients into a large bowl and beat until smooth.
Spread this mixture evenly over the bottom of the tin or dish. It looks as if their is never going to be enough but trust me their is. Arrange the plums on top, cut side up and sprinkle with the Demerara sugar to form a thick layer. Bake for 30 minutes, until golden brown.