Can I assemble this casserole the night before?
Yes, that's the whole point. Assemble completely, cover with foil, refrigerate overnight, then bake in the morning. The bread absorbs the custard as it sits.
What type of bread works best?
Use a sturdy bread like sourdough, challah, or brioche. Avoid soft sandwich bread, which gets mushy. Slightly stale bread works even better.
Can I make this ahead and freeze it?
Yes, assemble and freeze unbaked for up to 3 months. Thaw overnight in the fridge, then bake as directed, adding 10–15 minutes to baking time.
How do I know when the casserole is done baking?
The custard should be set but slightly jiggly in the very center. A knife inserted near the center should come out clean or with moist crumbs, not wet custard.
Can I use a different cheese?
Yes. Gruyère, Swiss, or a mild cheddar blend work well. Sharp cheddar adds the most flavor; use less of a milder cheese or the dish may taste bland.