Pre-heat your oven to 180 degrees Celsius/gas mark 4. Grease and line a 23cm spring form tin.
Peel and core the apples and slice into thin slices. Put them in a pan with the cinnamon, brown sugar and honey and cook very gently for around five minutes. Leave them to one side to cool.
In a clean bowl bowl (or stand mixer) add the caster sugar, honey, eggs, vegetable oil, cinnamon and vanilla and beat for around three to four minutes until pale.
Sift in the flour and baking powder and gently fold or mix the flour in with a metal spoon.
Pour 2/3 of the cake batter into the lined tin. Take a slotted spoon and spoon over the apples (drain away and juice and drink it!) Push the apples down a bit, then pour the rest of the cake batter over the top to cover the apples.
Bake for 35-40 minutes, or until a toothpick comes out clean when inserted into the centre of the cake. Keep an eye on the cake, if it starts to look too golden, place a piece of foil over the top half way through cooking.
Leave to cool before serving and dust with icing sugar. The cake will keep for up to five days in a tin.