French toast is a brunch and breakfast favorite, but standing over the stove preparing individual pieces for a group is challenging. The casserole version of French toast is an easy way to solve this problem, and you can flavor it in so many ways.
For best results, ensure the casserole refrigerates overnight to allow the potato bread to fully absorb the custard, leading to a richer texture. While potato bread offers a unique tender crumb, challah or brioche can be substituted for an even more decadent version. When preparing the lemon glaze, gradually add the lemon juice to the powdered sugar until a smooth, pourable consistency is achieved – you may not need all the juice. Avoid overbaking to keep the French toast casserole moist and tender; a slight jiggle in the center indicates it's perfectly set.