For the apple caramel, dice the apples. Put them in a saucepan with a knob of butter and set over a low heat. Add the sugar and vanilla. Stir until the mixture turns syrupy.
For the custard, whisk the milk with the egg and add the cinnamon and vanilla.
Dip each slice of bread into the mixture.
Melt butter in a frying pan and fry the bread. Cook on one side first, then sprinkle with sugar and turn again so that a golden crust forms. Keep the heat low, otherwise the sugar starts to burn.