Monte Cristo Breakfast Casserole
A Monte Cristo breakfast casserole takes the sweet and savory flavors of the classic sandwich—ham, Swiss, raspberry preserves, and honey mustard—and transforms them into an easy, make-ahead baked dish. Designed for low-stress mornings like Christmas, this overnight casserole soaks the bread in a rich egg custard for a custardy-crisp, family-favorite holiday breakfast.
A Monte Cristo Breakfast Casserole is the kind of dish that lets you love on your people and still actually sit and drink your coffee while they open presents. All the flavors of that classic sweet‑meets‑savory sandwich are tucked into an easy make‑ahead bake, so Christmas morning feels cozy instead of rushed.
Why This Casserole Works
This recipe layers sourdough, ham, Swiss, raspberry preserves, honey mustard, and a rich egg custard, then finishes with Gruyère and powdered sugar for that signature Monte Cristo touch. Because the sandwiches soak in the custard overnight, the bread turns custardy in the middle and crisp on top, giving you all the French‑toast vibes without any frying.
It’s also flexible: swap in cranberry‑orange bread, change up the cheese, or adjust the jam to what your family loves, and the method still works beautifully. Serve it with a big bowl of fresh fruit and extra jam on the side, and you have a full holiday breakfast with almost no last‑minute work.
Can I make this ahead?
Yes. Assemble the casserole, pour on the egg mixture, add the Gruyère, cover, and refrigerate for at least a few hours, overnight, or up to 2 days before baking.
Does the bread need to be a specific kind?
Mary Katherine uses a simple sourdough, but a cranberry‑orange or other berry bread works wonderfully and leans into the sweet side of a Monte Cristo.
How do I know when it’s done baking?
At 350°F, start checking around 35 minutes; the top should be golden and the center mostly set, with just a slight jiggle but no visible liquid. If it still seems soft in the middle, bake 3–5 minutes longer, since every oven runs a little differently.
What should I serve with it?
Fresh fruit and extra raspberry jam are perfect companions, and you can also offer a hot pepper raspberry jam for anyone who likes a little heat with their sweetness.
Is this healthier than a traditional Monte Cristo?
A classic Monte Cristo sandwich is dipped in batter and deep‑fried, while this version is baked, so you still get the same flavor profile without the frying oil. It’s still rich and special‑occasion worthy, but it feels a bit lighter on the plate.
Can I change the cheese or meat?
Yes. Swiss is traditional and Gruyère on top adds nuttiness, but you can swap in another good melting cheese, and use ham alone or a mix of ham and turkey if that’s what you have.
Monte Cristo Breakfast Casserole
Ingredients
For the sandwiches:
- 1 loaf sourdough bread 12 slices, enough to make about 6 sandwiches
- 16 oz thinly shaved deli ham
- 6 slices Swiss cheese
- Red raspberry preserves about ½–¾ cup, enough to spread one side of each sandwich
- Honey mustard about ¼ cup, generous layer on the other side of each sandwich
- Cooking spray or a little butter for greasing the 9×13 dish
Egg mixture and topping:
- 8 large eggs
- 1¾ cups milk
- 1 teaspoon kosher salt or a scant teaspoon, since ham and cheese are salty
- ¼ teaspoon black pepper or to taste
- About 4 oz shredded Gruyère cheese she buys a 6 oz bag and uses “close to 4 ounces”
- Powdered sugar for dusting after baking
To serve:
- Extra red raspberry jam or preserves for dipping; you can also offer a hot pepper raspberry jam if you like a little heat
Instructions
Prep the dish and bread
- Lightly grease a 9×13 baking dish with cooking spray.
- Lay out about 6 slices of sourdough on your work surface; you’ll make around 6 sandwiches from the loaf.
Build the sandwiches
- Spread each of the bottom slices generously with red raspberry preserves, covering the surface.
- Layer a hearty amount of thinly shaved ham on each slice (Mary Catherine starts with about 3 slices per sandwich and adds 1 more; use most or all of the 16 oz).
- Top the ham on each with 1 slice Swiss cheese.
- On the remaining bread slices, squirt on a generous amount of honey mustard and spread to the edges; don’t skimp, this adds a lot of flavor.
- Place the honey‑mustard slices on top to make full sandwiches.
Cut and arrange in the pan
- Slice each sandwich in half lengthwise.
- Cut each long half into about 4 triangles, so you end up with small sandwich wedges.
- Arrange the triangles upright in the greased 9×13 dish with the points standing up, wedging them in snugly; the dish will be very full and doesn’t need to look perfect.
Mix the custard
- In a bowl, crack 8 eggs and whisk until slightly beaten.
- Add 1¾ cups milk, the kosher salt, and black pepper, then whisk until well combined.
Pour and top
- Slowly pour the egg mixture evenly over all the sandwich pieces, letting it run between and around the triangles.
- Sprinkle about 4 oz shredded Gruyère over the top (you don’t need the full 6 oz bag).
Chill (overnight or up to 2 days)
- Cover the dish tightly and refrigerate at least a few hours, overnight, or up to 2 days so the bread can soak up the custard.
Bake
- When ready to bake, preheat the oven to 350°F.
- Uncover the casserole and bake for about 35 minutes, until the custard is mostly set and the top is golden and bubbly; depending on your oven, you may want to go 3–5 minutes longer if the center seems a little soft.
Finish and serve
- Let the casserole rest about 10 minutes after baking.
- Dust the top with a light coating of powdered sugar.
- Cut into portions and serve warm with a spoon or spatula, alongside dollops of red raspberry jam (and hot pepper raspberry jam if desired) for dipping.
Video
Notes
- This is designed as an overnight casserole, perfect for making 1–2 days before Christmas morning so you can be with your family instead of tied to the stove.
- Serve it with a big platter of fresh fruit for a simple sweet‑and‑savory breakfast that feels special but low‑stress.
Mine did not firm up. After 40 minutes at 350 F the custard portion was still mushy. Maybe my eggs weren’t large enough? I did measure 1 and 3/4 cups milk. I thought that was a lot at the time, but I trusted the recipe. Taste was good.
Yes, even though the recipe calls for 40 minutes, every oven can be different and it might need a little longer in yours!