This Baked French Toast Casserole is a fail-proof, crowd-pleasing way to serve up a fantastic brunch! It's one of my weekend go-to favorites. Prep can be done the night before, and bake it in the morning! (Note: The streusel amount listed is generous, for those who like a nice thick layer of crunchy topping. If you prefer, you can halve the amount of streusel.)