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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Can this be made in an 8×8 square dish? I do not have a 9×11.
Yes, you can use an 8×8 dish, but it will be a little deeper than if made in a 9×11.
A couple things to expect:
* You may need to add a little extra bake time
* Start checking near the original bake time, then add more as needed until the center is done
Just keep an eye on it and you should be fine!
~Donya
too make in a 9×11 dish Do you increase the ingredients? There is an * notation but didn’t see any further information
Great question! If you’re using a 9×11-inch baking dish (instead of something smaller like an 8×8 or 9×9), you typically don’t have to double the ingredients, but increasing them by about 25–30% is often a good idea to ensure the dish is full enough and still bakes up nicely. Enjoy! ~Donya
Most requested family favorite!
That just makes me so happy to hear! 💛 Knowing it’s your most requested family favorite is the best compliment I could ask for. Thank you for sharing that with me!
~Donya
Definitely a regular in our household!!
I love it, Crystal! Thank you. I’m thrilled you are cooking with me.
~Donya
Made this for dinner a couple of nights ago and had halved the recipe since it’s just the two of us…after the first bite, I wished that I had made the entire recipe. We had it with powdered sugar and pure maple syrup and think maple syrup is the way to go! This is a keeper!
I’m so glad you enjoyed the recipe! We never have leftovers of this one in my house! Thanks for your review!
My family loved it! Made exactly as recipe. Then I remembered I had some leftover prosciutto, I chopped some sweet onions with the prosciutto in the frying pan cooked just until onions were transparent, spread over cheese rested in fridge 30 minutes baked as directed.
That sounds heavenly, I’m glad you added your own twist! I’ll remember that nice addition! ~Donya
I love making this for meal trains, especially new moms. I bring it ready to bake along with a dinner and they can pop it into the oven in the morning for a delicious breakfast the whole family will enjoy. Thank for such a simple prep-ahead recipe that is so decadent!
I am thrilled you use my recipe for something so amazing! Thank you so much, these are the stories and reviews that I absolutely love to hear. ~Donya
I have made this several times for a mom’s group. Everyone loves it! I make as written but add some raspberry spreadable fruit on top of ham before cheese.
So every bite has a little sweet. Also bring the fruit spread on side if they want more.
Oh my gosh- that sounds like a great idea! Wow! Thank you for making my recipe, I’m so glad you’re here! ~Donya
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!
Preserves are a great addition to this dish. So glad you’re here! Thanks for the review! ~Donya
Super good!!! Made exactly as written. Thank you!
So glad to hear that. Enjoy! ~Donya