Have you ever made a breakfast casserole? They’re great for holidays or special days. You prep it the night before, then pop it in the oven in the morning. It keeps things simple, but also feels special and substantial. And the leftovers are so great for busy school mornings! The leftovers can even be cut into squares, wrapped well, and frozen.
Let’s get this casserole prepped and ready to go.
Tips For The Best Overnight Casserole Ever
One key to a really good overnight breakfast casserole is nothing more than time. Sitting overnight is really what makes this casserole awesome. The flavors have a chance to meld, the bread soaks in the egg and milk mixture adequately. And it’s pretty hands-off after it’s assembled.
Another key is using good bread. High quality sandwich bread, artisan bread, homemade bread, whatever you’ve got that has some substance to it will work. (Not that feather-light white bread.) And the bread should be slightly stale, because when it’s stale it will readily soak up the custard mixture (but fresh, soft bread will turn to goo).
To make this gluten-free, use (thawed) frozen shredded hash browns or use gluten-free artisan bread. Gluten-free sandwich bread will work, but the slices tend to be thinner.
The type of cheese you use also takes an ordinary breakfast casserole from ordinary or ho-hum to extraordinary. Gruyere, Swiss cheese, mozzarella, asiago, Monterey Jack, other types of cheddar, and really any kind of melting cheese works for this casserole.
If you’re using a mild-flavored cheese like those that aren’t aged for very long, try adding in a bit of another stronger flavored cheese.
A combo of sharp cheddar and Gruyere works well. And you could sprinkle the top with grated Parmesan or Romano too. You could also use feta or goat cheese. Neither melts, but the saltiness and creaminess, respectively, are hard to beat.
You can make a dairy-free versions with non-dairy milk and vegan cheese.
Find a very basic (read: picky eater-friendly) version below, but don’t be afraid to add vegetables in place of, or along with, the ham or protein of choice.
The possibilities are practically endless. You can swap the ham for country or other kinds of sausage, bacon, or ham. You can even make it with vegetarian sausage if you want.
A combination of roasted red peppers, onions, and goat cheese would be phenomenal. Add chopped broccoli, spinach, kale, chard, or another leafy green. Top with sautéed mushrooms! Add fresh or sun-dried tomatoes and fresh basil. Adding lightly cooked asparagus pieces or petite peas along with the ham is wonderful.
Oh. And caramelized onions! They are the greatest thing ever. This recipe calls for almost-caramelized onions. (See the recipe notes for more details.)
Make a Breakfast Casserole, Feed a Crowd
The other great thing about an overnight breakfast casserole is that it can feed a bunch of people — and it’s easy to make two at once. Heck, if you’re going to make one, may as well double it and make two!
As mentioned above, it’s great to make extra, because this casserole is perfect for cutting up, freezing or refrigerating, and reheating on busy mornings.
That being said, for a smaller group, the recipe can be easily halved and baked in an 8-inch square baking dish.
For a sit-down brunch or breakfast, serve this with roasted potatoes, fruit, and a simple green salad or roasted asparagus — which would totally be a delightful menu for a Mother’s Day Brunch.
Ham and Cheese Overnight Breakfast Casserole
- 2 tablespoons butter, plus more for baking dish
- 1 pound loaf artisan bread, cut into 8-12 slices
- 2 medium onions, diced (see notes)
- 12 large whole eggs
- 1 cup whole milk
- 1 cup cream
- 1 tablespoon Dijon mustard (or 1 tsp. dry mustard)
- 2 teaspoons dried ground sage (optional)
- 1/4 teaspoon salt
- 1/4 teaspoon freshly ground black pepper
- 2 cups cooked ham, diced
- 1/4 cup chopped fresh chives, plus more for garnish
- 8 ounces cheddar, gruyere, or Swiss cheese, shredded
- Fresh parsley, chopped, for garnish
- Butter an 9- by 13-inch or 3-quart casserole dish. Cut the bread slices to fit on the bottom of the dish, using any scraps to fit into the empty spaces. You may not need all of the bread.
- In a large heavy-duty skillet or Dutch oven, melt 2 tablespoons butter over medium-high heat. Add diced onions. Sauté until onions start to soften; lower heat and allow onions to caramelize, if desired. (This will take about 30 minutes on medium-low heat.) Set aside until ready to assemble casserole.
- Whisk eggs with milk and cream. Add the Dijon mustard, ground sage (if using), salt, and pepper. Set aside.
- Spread caramelized onions evenly over the sliced bread. Top with an even layer of diced ham and sprinkle with chives, followed by shredded cheese.
- Pour the egg/milk mixture over the top of the bread. Gently press down on bread or tilt pan, if necessary, so the egg mixture is evenly distributed and all of the bread has been soaked with the mixture. Cover with foil or plastic wrap. Refrigerate overnight.
- The next morning, remove casserole from the fridge and let stand at room temperature while preheating oven to 350°F. Set oven rack to lower middle position.
- Bake casserole for 30 minutes covered with foil or casserole lid. Uncover and continue baking for another 15-18 minutes to allow top to become golden and bubbly. The center of the casserole should just be set. If the eggs are still runny, bake for another 3-5 minutes and check again. Let casserole stand a few minutes, lightly covered, before cutting into squares and serving. Garnish with chives and parsley.
Serving suggestions: roasted potatoes, fruit, and green salad or roasted vegetables.
- While the caramelized onions are definitely worth the effort, to save time, regular sautéed onion can be substituted. Add one onion to the pan and sauté until softened. Cool slightly before assembling casserole.
- If adding vegetables, reduce amount of ham to 1 cup and substitute up 1 1/2 to 2 cups tender crisp broccoli, asparagus, peas, or other veggie.
- Cream can be substituted with milk or half-and-half to cut down on the richness.
Photos and recipes by Lindsey Rose Johnson for Design Mom.