Okay, be honest with me: ever find yourself staring into the fridge thinking, “Can I just use up this leftover ham, or am I about to invent something questionable?” Well, my answer to that dilemma is this Monte Cristo French Toast Casserole. I first tried cobbling this together at 9pm before an early brunch when I realized making individual sandwiches was, frankly, way too much faff. My laziness? Led to greatness. Also, this dish always reminds me of the time my cousin tried to cook the original sandwich on a campfire skillet—long story short, don’t do that; cheese everywhere.

Why I’m Obsessed With This (And Maybe You Will Be Too)

I make this casserole when I want to seem like a brunch hero with about ten minutes of actual effort (and maybe two bowls to wash). My family goes bananas for this every Christmas morning (and sometimes just random Sundays when I forget to do a proper grocery shop). There’s something about the crispy-soggy, ham-cheesy layers that turns reasonable adults into greedy snack goblins. Plus—you can assemble it the night before. Seriously, that’s a gamechanger for folks who want to be upright but not alert before noon.

Let’s be real though: trying to slice it neatly is a lost cause when everyone just wants the gooey middle bit; pro tip—just dig in, it’s less stressful.

Here’s What You’ll Need (But Don’t Stress Over It)

8–10 thick slices of white bread (Brioche is my go-to, but honestly, supermarket sandwich bread works if that’s what you’ve got. My gran swore by a crusty farmhouse loaf.)
8–12 slices of deli ham (Sometimes I use smoked turkey if I’m feeling wild, or whatever’s trying to escape the meat drawer.)
8 slices Swiss cheese (Gruyère will make it posh; cheddar if you can’t be bothered—I’m not the cheese police.)
4 large eggs
1 ½ cups whole milk (I’ve been known to sneak in some half-and-half if it’s kicking about, just don’t use skim—it’s no fun.)
2 tablespoons Dijon mustard (Yellow mustard in a pinch, or leave it out, though—no strong feelings either way.)
1 tablespoon maple syrup (Or honey. Aunt Jemima isn’t going to knock on your door, I promise.)
Salt and black pepper, just a little
Powdered sugar and extra maple syrup, for serving (and dusting, if you want to show off)

How To Actually Make This (Even If You’re Rushed)

First, grease a 9×13 in (ish) baking dish with butter or spray. I literally just tear off a hunk of butter and rub it around—super technical, I know.
Layer half of your bread slices at the bottom. You can tuck and fold to make them fit; no one’s getting a ruler out.
Layer on the ham, then do a layer of cheese.
Now top with the remaining bread slices. (If bits are wonky, that’s fine; ugly casseroles taste the best.)
In a biggish bowl, whisk together the eggs, milk, Dijon, a dab of maple syrup, plus a good pinch each of salt and pepper.
Pour that over everything, and gently press down with your hands or a spatula so the bread soaks it up. This is where I usually sneak a corner taste if no one’s watching. Cover and let it sit at least half an hour—overnight is even better if you manage to think ahead.
When you’re ready: preheat your oven to 350°F (175°C). Bake, uncovered, for around 40–45 minutes. If it starts getting too brown, sometimes I loosely plop a bit of foil on top. It should be puffy and golden, with cheese bubbling up.

Don’t worry if it looks like a bread volcano midway, it’ll settle once you let it cool a tick.
Let it rest for 10 minutes. Dust with powdered sugar and drizzle with maple syrup. Then slice, serve, and brace yourself for chaos.

Lived and Learned: Notes from the Casserole Trenches

I find this works better if you let the bread soak for longer (overnight in the fridge is my MVP move, but I’ve made it with just a 15-minute dunk and didn’t get complaints—my standards might just be lower than I think).
Don’t skimp on the cheese. Seriously, I tried being “good” once—regretted it. Go ham (sorry) on the ham too.
If you like crispy edges, use slightly stale bread. Fresh bread makes it softer—nothing wrong with that in winter.
The first time I tried to use almond milk, it came out a bit watery—probably won’t do that again, but hey, try it if you must.

Experiments and Weird Variations

I once swapped out ham for roast chicken—tasted fine, but it didn’t really hit the Monte Cristo vibe. Fun, but not quite right.
Brioche plus a handful of baby spinach tucked in makes me feel almost healthy. Or throw in some caramelized onions if you’re feeling posh (works better than you’d think!).
Tried a gluten-free loaf once—it didn’t soak up well, kinda sad, so I usually give that a miss, but your mileage may vary.

What You Need (And What to Do If You Don’t Have It)

Big baking dish—9×13 in is classic, but honestly, I once crammed everything into an old lasagna pan and it turned out just fine.
Mixing bowl—if you don’t have one big enough, just use a soup pot; nobody’s going to report you to the bowl police.
Whisk or fork, whatever’s nearest.

How Long Will It Last? (Hint: Not Long!)

If you’ve got the self-restraint of a saint, you can keep leftovers covered in the fridge for 2–3 days. Reheat in the microwave or oven, though honestly, in my house it never lasts more than a day. I blame my husband and his suspiciously large “tasting” slices.

Serving—Make It Yours

I always serve this with a mound of fresh berries and a pile of crispy potatoes on the side. Once we tried with storebought jam right on top like the restaurant versions—kids loved it; adults were split. Coffee is non-negotiable, in my humble opinion, and if you want to be fancy, serve mimosas (we do this for grown-ups at brunch-shower things; makes everyone very happy!).

Lessons Learned The Hard Way (“Pro” Tips!)

I once tried rushing and baked it from cold straight out of the fridge—don’t do this! It stays soggy in the center. Let it come up closer to room temp if you can wait (but I get it, waiting is hard).
Trying to go light on grease? Just be prepared for mega stickage. Grease the dish proper, trust me.
I forgot to cover it once for the overnight soak and it dried out. So, if you remember, cover it. Foil, cling film, or chuck a clean tea towel on top; whatever.

Questions Folks Actually Ask Me (For Real)

Can I freeze Monte Cristo French Toast Casserole?
Yeah, technically—it freezes fine after baking, but the texture gets a bit soggy once thawed. If you do freeze, warm it up in the oven for best results; I’ve done this for meal trains, and no one complained too much.
What if I don’t have Swiss cheese?
Cheddar or mozzarella work fine. So does sliced provolone. Actually, goat cheese is a no-go—learned that the hard way, just tastes odd here.
Is this sweet or savory?
A bit of both! It’s got that French toast sweetness, but the ham and cheese bring it back down to earth. If you want more sweet, try a heavier drizzle of syrup or even fruit jam (strawberry is classic—like they do on classic Monte Cristos).
Can I make this dairy free?
Technically, yes, but I find dairy-free cheese gets weird when baked, and you want that melty goo. Never say never, though! Minimalist Baker has good tips for veganizing French toast generally.
How should I reheat leftovers?
A quick zap in the microwave works, though the oven crisps it back up better. Actually, now that I think of it, air fryer slices are an adventure (messy, but tasty!).

Oh—and if you can’t find your sieve for powdered sugar, just skip dusting it or use a tea strainer. The world won’t end. Now, off you go—enjoy the lazy magic of Monte Cristo French Toast Casserole, preferably in pajamas and fuzzy socks (that’s non-negotiable in my house, by the way).

Monte Cristo French Toast Casserole