This cake has been made at Ballymaloe for years. We even have guests who ask for it specifically every time they visit. The fruit sinks to the bottom as it cooks, leaving a light sponge on top with a lovely sugary crust. Makes 12-16 squares.
Raspberry and pear: Instead of the cinnamon, mix the finely grated zest of 1 orange into the batter. Instead of the apples, sink 100g (31/2oz) fresh or frozen raspberries and thin slices of 2 pears into the batter and cook in the same way.