5 Star Reader Comment
My family lives this! I’ve made it 3 times already! It’s so easy and perfect for a special brunch. We drizzle with warm preserves and sprinkle with powdered sugar…yum!
Lynn
Why You’ll Love This One
There’s a reason this shows up on my table every Christmas morning and just about every time we have a house full of people. It’s the breakfast that looks like you got up at dawn and fussed — golden and puffed, buttery croissants soaking up a rich custard, ham and cheese melting into every corner — when the truth is you did the work the night before in about ten minutes.
I’ve leaned on this casserole for years: sleepy holiday mornings, overnight guests, the mornings when I want to sip my coffee instead of stand at the stove. You pull it out of the fridge, slide it in the oven, and it takes care of itself while everybody wanders in following the smell.
If you’ve ever felt like hosting breakfast is more than you can pull off — this is the recipe that proves it isn’t.
Enjoy!
Donya’s Tips and Things to Know
- Bakery croissants, every time. They hold their shape and soak beautifully.
- Don’t skip the soak. It’s the difference between custardy and crumbly.
- Shred your own cheese. Pre-shredded is coated to keep it from clumping, and it never melts quite as dreamy.
- Let it rest before you cut in, so it sets up and slices clean.
Breakfast lovers add crock pot Southern grits and fruit salad. Your family will love you even more for it!
Ingredients You’ll Need
Nothing fancy here, and that’s the beauty of it. A few good things, doing a lot of work:
- Croissants — grab real ones from the bakery section, not the kind in a tube. Day-old is even better; they drink up the custard without going to mush.
- Eggs and half-and-half — the backbone of that rich, custardy middle. Whole milk works if that’s what you’ve got.
- Dijon mustard — my little secret. Just enough to wake everything up without tasting like mustard.
- Ham — deli ham or last night’s leftovers both shine here.
- Swiss or Gruyère — nutty, melty, and worth shredding yourself off the block.
- A dusting of powdered sugar — trust me on the sweet-and-savory finish.
How To Make Overnight Ham and Cheese Breakfast Casserole
Tear the croissants and tuck them into your dish with the ham and cheese scattered all through — not just on top, but down in the layers where every bite gets some. Whisk your eggs, half-and-half, Dijon, and a pinch of salt, and pour it evenly over the top so every piece gets a soak. Cover it, chill it, then bake until it’s golden and puffed and the middle is set. Rest it a few minutes, dust with powdered sugar, and carry it to the table.
Make It the Night Before
This is the part I love most. Assemble everything tonight, cover it, and let it sit in the fridge overnight. That long soak is what gives you that soft, custardy center instead of dry bread — so an overnight rest isn’t just convenient, it actually makes it better. In the morning, all that’s left to do is bake. (Short on time? Even 30 minutes of chilling will do.)
More From My Kitchen To Yours
Ingredients
- 6-8 medium-sized croissants
- 4 large eggs
- 1 cup half and half or whole milk
- 1 ½ tablespoon Dijon mustard
- pinch of salt
- 8 ounces deli or leftover ham (about 6 thin slices)
- 6 ounces shredded swiss or gruyere cheese
- powdered sugar
Instructions
- Lightly coat a 9×6 deep baking dish with cooking spray. **A 9×11 baking dish can also be used.**
- Tear croissants in half and place in prepared pan. Cut ham into thirds and nestle around the croissants. Sprinkle on shredded cheese.
- In a small bowl, whisk together eggs, half and half, Dijon mustard, and salt. Pour over croissants. Cover with foil and chill in the refrigerator for 30 minutes or overnight.
- Heat oven to 350 degrees. Place covered breakfast casserole in the oven and bake for 20 minutes. Remove the foil and continue to bake for another 10 to 15 minutes until hot and bubbly with a golden top.
- Remove casserole from the oven and let rest for 5 minutes. Sprinkle with powdered sugar and serve.
Video
Nutrition
Easy Variations
Make it yours — this recipe is forgiving:
- No croissants? Buttery brioche or challah stand in beautifully.
- Swap the ham for cooked, crumbled breakfast sausage or crispy bacon.
- Trade Swiss for sharp cheddar or pepper jack if you like a little bite.
- Fold in sautéed spinach, mushrooms, or caramelized onions for something a little more brunchy.
How to Store, Freeze & Reheat
Leftovers keep well, covered, in the fridge for 3 to 4 days — reheat individual squares in the microwave, or warm the whole pan in a low oven so the edges crisp back up. To freeze, cool it completely, wrap it tight, and it’ll keep up to 3 months; thaw overnight in the fridge before reheating.
FAQ with Answers
A few easy wins:
Use croissants that are a little stale (or let torn croissants sit out 30–60 minutes).
Give it chill time so the custard absorbs evenly.
Bake until the center is set (no wet jiggle in the middle), then let it rest before slicing.
Thin-sliced deli ham layers in beautifully and makes this extra easy. Leftover holiday ham works too—just slice or chop it into bite-size pieces so it distributes well.
Yes. Whole milk works fine. For an even richer bake, you can use a mix of milk + a splash of heavy cream. I don’t love using low-fat milk here—it can bake up a little less creamy.
Oven is best: cover loosely with foil and warm at a low temperature until heated through. The microwave works, but it softens the croissant texture more.
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This was a big hit for Christmas morning! I made 8 sandwiches, and by the time it was done cooking there was much egg. I’ll probably add a couple next time.
Thanks, JL!
~Donya
This was so easy and it came out looking just like the picture with the recipe. Also it tasted great. It truly was like a monte cristo sandwich without the fuss. I put it together before bed on Christmas eve so it could soak up the eggs and cream. This will definitely be a keeper and may make for a easy dinner sometime.
I’d like to make this recipe but just wondering why powdered sugar is sprinkled on since it’s a savory dish. Thanks for the prompt reply.
That’s how we like it! Sweet and savory. So good.
~Donya
Amazing!
Thanks so much, Melissa!
~Donya
Anyway to make this amazing casserole without eggs? My grandson is allergic, it looks fabulous
Everyone loved this casserole. Super easy to make. If you love quiche you will love this, very similar in texture.
I would like to make it in the 9×13 dish and just confirming that you don’t change your portion recommendations, ie more eggs, more half& half to accommodate the change in pan size. Thanks so much.
I’ve made this twice over the holidays. This really is superb! I grated fresh Gruyère for the cheese.
Super simple to make and delicious. We all loved it!
Is the given 20 + 10 minute cook time for a 9×6 pan or 9×11? Trying to figure out if I should adjust the time for a 9×13 or not. Thanks
If i use 8 croissants in this recipe do i need to increase the egg mixture?
Would this be ok to bring to work the next morning? We have a microwave but no oven to warm it up. I’m just wondering if it would be “rubbery” being warmed up in the microwave.
Sure! Heating in the microwave is not a problem. I would do it in 30 second time frames. Enjoy!
~Donya