Preheat the oven to 180 ° C and grease a flat baking dish. Brush the bread slices with the butter, layer them like a roof tile in the pan and dust with cinnamon.
Whisk the milk, sugar, vanilla sugar, salt and eggs well and pour over the bread, leave to stand for 10 minutes. Press the bread firmly into the liquid several times.
Sprinkle with chocolate sprinkles. Bake for about 55 minutes, then leave to cool for 30 minutes.