I realize it's too late to do this for Christmas morning....
my wife makes an OVERNIGHT BRIOCHE CASSEROLE (lots of recipes available online) for christmas morning everey year
we start with a loaf (or two) of Brioche bread,
slice or tear it up, and leave out for about a day to dry out
then shred it up an put in a casserole dish
mix eggs (6-8 per loaf) with cream (or milk cream mixture) (1 cup per loaf), vanilla, a little salt and sugar (Brioche bread has sugar already)
pour over shreaded bread and place in refrigerator over night
in the morning, preheat oven to 350-400
mix brown sugar, cinnamin, and butter to make a crumble and sprinkle on top of the egg/bread mixture
cover with foil
place into the oven for 30 -35 min,
remove foil and give it another 10 min to give the top a little crust
my family loves it