Throw 500g peeled, cored and chopped apples into a greased and lined 20cm deep loose-bottomed tin. Mix together 75g self-raising flour, 1tsp baking powder, 125g caster sugar, 6tbsp milk, 4tbsp sunflower oil and 2 medium eggs. Pour over the apples and bake at 170C/Gas 3 for 45 min until risen and golden. While it’s cooking beat together 75g unsalted butter, 100g caster sugar and 1tsp vanilla essence. Pour over the cake and return to the oven for another 30 min. Leave to cool in the tin, then remove lining paper and sprinkle top with icing sugar to serve.