This cake is delicious eaten warm with a cup of tea or with lashings of creamy custard as a pudding.
Preheat the oven to 180*c/Fan oven 160*c/Gas mark 4. Grease and line an 8in/20cm square cake tin. Core and coarsely grate one apple.
Sift the flour into a large bowl and stir in the oats, cinnamon, salt, sugar and raisins. Beat in the melted butter, eggs, milk and grated apple and pour into the prepared tin.
Scatter over the granola. Quarter, core and slice the remaining apples and scatter randomly over the top of the cake, pushing them into the cake mixture slightly. Bake for 1 hour to 1 hour 15 minutes or until a skewer inserted into the centre of the cake comes out clean. Allow to cool before dusting with icing sugar and cutting into 16 squares.
This cake mixture works well with pears to replace the apple. Or, make up the cake mixture and omit the apple slices for the topping and replace with 150g blackberries or raspberries or blueberries.