Put half the apple slices in a small saucepan with the water, then cover and simmer for 5 minutes until pulpy. Put the remaining apple slices in a bowl of cold water with a little lemon juice.
Mix the flour, baking powder, half the ground cinnamon and all of the ginger and nutmeg together in a mixing bowl.
Cream the reduced-fat spread with 150 g (5 oz) of the sugar in another bowl. Gradually mix in alternate spoonfuls of beaten egg and flour mixture until all has been added and the mixture is smooth. Stir in the cooked apple.
Pour the mixture into a lightly oiled 23 cm (9 inch) spring-form cake tin and spread the surface level. Drain the remaining apples well and arrange the slices in rings on top of the cake mixture. Sprinkle with the remaining sugar and cinnamon. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 35–40 minutes until well risen and a skewer inserted into the centre comes out clean.
Serve the cake while still warm, on its own or as a pudding with crème fraîche, yogurt or custard.