Layer the slices of bread in the dish. Combine the milk, vanilla sugar, cinnamon and salt, pour over the bread, set aside.
Bring the sugar and water to the boil in a wide pan without stirring, reduce the heat and simmer, swirling the pan occasionally, until a light brown caramel has formed. Remove the pan from the heat. Add the cream, butter and salt, simmer over a low heat until the caramel has dissolved. Remove the pan from the heat, allow to cool slightly. Stir in the eggs and crème fraîche.
Plum bread bake
Arrange the plums between the slices of bread, pour over the sauce, top with the butter. Cover the dish with foil.
Bake for approx. 15 mins. in the bottom half of an oven preheated to 200°C. Remove the foil and cook for a further 35 mins. Remove from the oven, serve warm.