Cube the challah bread and lay in an even layer in your glass baking dish. No need to grease or prepare the baking dish in any way.
Place the remaining french toast casserole ingredients into a high speed blender and blend until a smooth custard forms, approximately 3 minutes.
Pour the custard over the cubed bread and cover the casserole with plastic wrap. Place in the fridge overnight until ready to bake.
When ready to bake, preheat the oven to 350.°
While the oven is preheating, prepare the praline topping (if using): in a small dish, mash all of the praline ingredients together with a fork until roughly combined.
Remove the plastic wrap and sprinkle the praline topping over the casserole.
Bake for 35-40 minutes, or until the topmost pieces of bread begin to turn golden brown.
If desired, drizzle the casserole in sugar glaze before serving*