Ah, another weekend breakfast dish. I feel bad posting this on a Sunday night- if your life is like mine, you won't be able to make this until Saturday morning at the earliest, which is a long ways away.
This is one of those recipes I make as is, with only one teeny tiny change. Instead of challah/brioche, I use cinnamon bread. The loaf I made for the recipe (yes, I bake much of the bread we eat) was 1.5 lbs. Larger than what the recipe called for, but it worked well in a 9x13 pan. There's no need to bake bread for this recipe, although I do caution you to start with unsliced bread. I cut mine into 1-2 inch thick chunks and give it to the kids to break into bite size pieces and toss them into the pan. Keeps them busy, and only minor vacuuming is needed after to clean up all the crumbs from the floor. If you start with pre-sliced bread, I think the bites will be too small as one dimension will always be defined by the slicer.
While my cinnamon bread would make wonderful 'regular' french toast, it is nice to have a breakfast where I'm not stuck at the stove. So here it is-- enjoy! http://cooktj.com/french-toast-baked-casserole