Whisk together the milk, cream, eggs, vanilla seeds, and 1 teaspoon of the cinnamon and pour half of this mixture all over the bread. When it has soaked in slightly, arrange the bread in the baking dish so the pieces are overlapping. Continue layering the bread until all the pieces have been used, then pour over the rest of the egg mixture and scatter the surface with the remaining sugar and a light dusting of cinnamon.