I still remember the first time I made an overnight breakfast casserole for a house full of guests. I was half-awake, half-panicked, and convinced I'd ruined brunch. Then I pulled a bubbling, golden pan out of the oven and everyone went quiet in the best way. This is that recipe, inspired by Ina Garten's famously unfussy style.
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Here's the magic: you do all the work the night before. Bread, eggs, milk, cheese, and a little mustard go into a baking dish, then the fridge does the rest while you sleep. In the morning you slide it into the oven and get on with your coffee.
If you've ever stood at the stove flipping eggs for a crowd, this is your way out. One pan, zero last-minute scrambling, and a casserole that tastes like you fussed for hours. You didn't. Nobody has to know.
Why You'll Love This Recipe
About the Ingredients
10 cups (about 300g) day-old French or sourdough bread, cut into 1-inch cubes
Stale bread is the secret here because it soaks up custard without turning to mush; if yours is fresh, spread the cubes on a sheet pan and dry them in a 300F (150C) oven for 10 minutes. A crusty Italian loaf or even cubed bagels work beautifully as a swap.
1 pound (450g) mild or hot Italian sausage, casings removed
You can substitute an equal weight of breakfast sausage, crumbled bacon, or diced ham; if you go the ham route, skip the browning step and just layer it in. Buy sausage the day you assemble it for the best flavor.
1 large yellow onion, diced (about 1 1/2 cups)
Sweet onion or two shallots can stand in if that's what you have. Frozen diced onion (about 1 1/2 cups, no need to thaw) is a legit time-saver on busy weeks.
1 red bell pepper, seeded and diced (about 1 cup)
Any color bell pepper works, and a handful of frozen fire-roasted peppers adds a nice smoky note. If peppers bother your stomach, swap in 1 cup of sliced mushrooms instead.
8 large eggs
Room-temperature eggs blend into a smoother custard, so pull them out 30 minutes ahead if you can remember. For a slightly lighter set, use 6 whole eggs plus 2 extra whites.
2 cups (480ml) whole milk
Whole milk gives the creamiest result, but half-and-half makes it richer and 2 percent works in a pinch. For a dairy-free version, use unsweetened oat milk plus 1 extra tablespoon of olive oil.
1 cup (240ml) heavy cream
Half-and-half is the closest substitute; if you want it lighter, use 1 cup whole milk instead and expect a slightly softer set. Don't use fat-free anything here, or the custard turns watery.
2 cups (about 225g) shredded sharp cheddar cheese, divided
Sharp cheddar brings the flavor, but Gruyere, Monterey Jack, or a bag of Mexican blend all melt beautifully. Buy a block and shred it yourself if you can, since pre-shredded cheese is coated and melts a little less smoothly.
1 tablespoon Dijon mustard
Dijon adds a subtle tang that keeps the casserole from tasting flat; yellow mustard is a fine substitute in a pinch. If you're out of both, a teaspoon of dry mustard whisked into the eggs does the job.
1 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper
Kosher salt is less salty by volume than table salt, so if you only have table salt, start with 3/4 teaspoon. Taste your cheese and sausage first, since salty brands may need less.
2 tablespoons unsalted butter, plus more for the dish
Salted butter works if you cut the added salt slightly. A neutral oil like avocado oil can replace the butter for browning the vegetables.
2 scallions, thinly sliced, for serving (optional)
Fresh chives or parsley are great swaps, and a spoonful of salsa or hot sauce on top is never a bad idea. Skip the garnish entirely if you're feeding picky eaters.
Tips & Tricks
- Don't skip the overnight soak. The bread needs at least 8 hours in the fridge to absorb the custard, and that soak is what makes the inside tender instead of dry or soggy.
- Cook your sausage and vegetables first and let them cool slightly. Raw sausage releases fat and water in the oven, which can make the casserole greasy and slow to set.
- Use day-old or lightly dried bread. Fresh soft bread turns to paste, so if yours is squishy, toast the cubes briefly before layering.
- Check the center, not just the top. A casserole can look golden while the middle is still liquid, so aim for 160F (71C) in the center or a knife that comes out clean.
Pro Tips
Step-by-Step Instructions
1. Butter and prep the dish
Butter a 9×13-inch baking dish generously, getting into the corners so nothing sticks. Set it aside and preheat nothing yet, since this casserole goes into the fridge overnight.
2. Brown the sausage
Heat a large skillet over medium-high heat, about 375F (190C) on an electric skillet, and cook the sausage for 6 to 8 minutes, breaking it up with a spoon, until no pink remains and the edges are browned. Transfer it to a plate lined with paper towels to drain.
3. Soften the vegetables
Pour off all but 1 tablespoon of the sausage fat, add the 2 tablespoons butter, and cook the onion and bell pepper over medium heat for 5 to 6 minutes until softened and lightly golden. The vegetables should look glossy and smell sweet, not browned.
4. Whisk the custard
In a large bowl, whisk the eggs, milk, cream, Dijon, salt, and pepper for about 1 minute until completely smooth and slightly frothy. Whisking well is what gives you a silky custard instead of streaks of egg white.
5. Layer the casserole
Spread half the bread cubes in the prepared dish, then scatter on half the sausage, half the vegetables, and 1 cup of the cheddar. Repeat with the remaining bread, sausage, vegetables, and cheese, pressing down gently so everything fits in an even layer.
6. Pour and soak
Pour the custard evenly over the top, pressing the bread down with a spatula so it soaks. Cover tightly with foil and refrigerate for at least 8 hours or up to 24 hours.
7. Bake until golden
Preheat the oven to 350F (175C). Bake the covered casserole for 25 minutes, then uncover and bake another 25 to 30 minutes, until the top is deeply golden brown, the edges are bubbling, and the center reads 160F (71C) on an instant-read thermometer. If the top browns too fast, tent it loosely with foil.
8. Rest and serve
Let the casserole rest for 10 minutes so the custard sets, then scatter on the scallions and slice into squares. Serve warm with hot sauce or salsa on the side.
Delicious Variations
Vegetarian Garden Version
Skip the sausage and add 2 cups of sauteed spinach, mushrooms, and zucchini; use 2 1/2 cups cheese for extra richness.
Southwest Kick
Swap the Italian sausage for chorizo, use pepper Jack cheese, and stir 1 can of drained green chiles into the custard.
Ham and Swiss Brunch
Replace the sausage with 2 cups diced ham and the cheddar with shredded Gruyere for a classic, slightly nutty twist.
How to Store Make Ina Garten's Easiest EVER Overnight Breakfast Casserole!
Refrigerator
Store leftovers covered in the fridge for up to 4 days; reheat single portions in the microwave for 60 to 90 seconds.
Freezer
Freeze baked and cooled squares tightly wrapped for up to 2 months; thaw overnight in the fridge before reheating.
Reheating
Reheat in a 325F (165C) oven for 15 to 20 minutes, covered, until hot through, or microwave individual servings for about 1 minute.
Frequently Asked Questions
Q: Can I make this overnight breakfast casserole ahead of time?
Yes, and that's the whole point. Assemble it up to 24 hours ahead, cover it tightly, and keep it in the fridge until you're ready to bake. If you go longer than 24 hours, the bread gets too soft and the casserole turns mushy.
Q: How do I know when the casserole is fully cooked?
The center should read 160F (71C) on an instant-read thermometer, and a knife inserted in the middle should come out clean. The top will be golden brown and the edges will bubble, but always check the middle since that's the last part to set.
Q: Can I use a different kind of bread?
Absolutely. Day-old French, sourdough, Italian, or even cubed bagels all work, as long as the bread is somewhat stale. Avoid soft sandwich bread, which dissolves into the custard and makes the casserole gummy.
Q: Why is my breakfast casserole watery?
The usual culprits are undercooked eggs, watery vegetables like frozen spinach that weren't squeezed dry, or too much milk. Cook your vegetables first, drain any meat well, and bake until the center hits 160F (71C).
Q: Can I halve this recipe?
Yes, use an 8×8-inch dish and cut every ingredient in half, then start checking for doneness about 10 minutes earlier. The bake time shortens because a smaller dish heats through faster, so rely on the thermometer rather than the clock.
Give this overnight breakfast casserole a try this weekend and let the fridge do the heavy lifting while you sleep. Assemble it tonight, bake it golden tomorrow, and watch your table go quiet in the best way. Small steps, big impact.
Make Ina Garten's Easiest EVER Overnight Breakfast Casserole!
Ina Garten's easiest overnight breakfast casserole is a creamy, cheesy make-ahead crowd-pleaser you assemble tonight and bake golden tomorrow morning.
🧂 Ingredients
- 10 cups (about 300g) day-old French or sourdough bread, cut into 1-inch cubes
- 1 pound (450g) mild or hot Italian sausage, casings removed
- 1 large yellow onion, diced (about 1 1/2 cups)
- 1 red bell pepper, seeded and diced (about 1 cup)
- 8 large eggs
- 2 cups (480ml) whole milk
- 1 cup (240ml) heavy cream
- 2 cups (about 225g) shredded sharp cheddar cheese, divided
- 1 tablespoon Dijon mustard
- 1 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper
- 2 tablespoons unsalted butter, plus more for the dish
- 2 scallions, thinly sliced, for serving (optional)
📋 Instructions
- 1Butter and prep the dish — Butter a 9×13-inch baking dish generously, getting into the corners so nothing sticks. Set it aside and preheat nothing yet, since this casserole goes into the fridge overnight.
- 2Brown the sausage — Heat a large skillet over medium-high heat, about 375F (190C) on an electric skillet, and cook the sausage for 6 to 8 minutes, breaking it up with a spoon, until no pink remains and the edges are browned. Transfer it to a plate lined with paper towels to drain.
- 3Soften the vegetables — Pour off all but 1 tablespoon of the sausage fat, add the 2 tablespoons butter, and cook the onion and bell pepper over medium heat for 5 to 6 minutes until softened and lightly golden. The vegetables should look glossy and smell sweet, not browned.
- 4Whisk the custard — In a large bowl, whisk the eggs, milk, cream, Dijon, salt, and pepper for about 1 minute until completely smooth and slightly frothy. Whisking well is what gives you a silky custard instead of streaks of egg white.
- 5Layer the casserole — Spread half the bread cubes in the prepared dish, then scatter on half the sausage, half the vegetables, and 1 cup of the cheddar. Repeat with the remaining bread, sausage, vegetables, and cheese, pressing down gently so everything fits in an even layer.
- 6Pour and soak — Pour the custard evenly over the top, pressing the bread down with a spatula so it soaks. Cover tightly with foil and refrigerate for at least 8 hours or up to 24 hours.
- 7Bake until golden — Preheat the oven to 350F (175C). Bake the covered casserole for 25 minutes, then uncover and bake another 25 to 30 minutes, until the top is deeply golden brown, the edges are bubbling, and the center reads 160F (71C) on an instant-read thermometer. If the top browns too fast, tent it loosely with foil.
- 8Rest and serve — Let the casserole rest for 10 minutes so the custard sets, then scatter on the scallions and slice into squares. Serve warm with hot sauce or salsa on the side.
Maya writes about sustainable living and zero-waste practices, focusing on small, actionable changes for everyday life. She shares practical tips from her own experiments in reducing plastic and food waste.
