Quick Recipe Overview
Prep 20 minutes; cook 45 minutes; additional 40 minutes; total 105 minutes. Yield 8 slices. Breakfast, American. Difficulty: easy.
Intro
This Christmas morning breakfast casserole is a savory, make-ahead pan of soft bread, set eggs, spinach, sweet red pepper, and melted cheddar. The short rest lets the bread absorb the custard, so breakfast can go into the oven while everyone gathers.
Why You’ll Love This Recipe
One baking dish serves eight without cooking separate eggs to order.
The red pepper and spinach add holiday color using everyday vegetables.
You can assemble it the night before and bake in the morning.
Recipe Card

Christmas Morning Breakfast Casserole with Spinach and Cheddar
Ingredients
Equipment
Method
- Heat the oven to 350°F and lightly grease a 9-by-13-inch baking dish.
- Heat olive oil in a skillet over medium heat. Cook red bell pepper for 4 minutes, then stir in baby spinach until wilted, about 2 minutes. Cool briefly.
- Whisk large eggs, whole milk, kosher salt, and black pepper in a bowl until fully blended.
- Spread day-old bread cubes in the dish. Scatter the cooked vegetables and shredded cheddar cheese over them, then pour the egg mixture evenly over everything.
- Press the bread gently into the custard and refrigerate for 30 minutes, or cover and chill overnight.
- Bake uncovered for 40 to 45 minutes, until the top is golden and the center is set with no liquid egg. Rest 10 minutes before slicing.
Notes
Recipe Tips
Use slightly stale bread. Fresh soft bread can turn pasty after soaking.
Cool the sautéed vegetables briefly so they do not start setting the eggs before baking.
Check the center with a knife; it should come out without wet egg. Let the pan stand before cutting.
Cut the bread into roughly even cubes so the custard reaches every piece at the same rate. If the bread is very fresh, spread the cubes on a baking sheet for 10 minutes in a 300°F oven, then cool them before layering. This helps the squares hold together after baking.
If the top browns before the center sets, loosely tent the pan with foil for the final 10 minutes. A 9-by-13-inch glass dish may bake a little differently from metal, so rely on the set center rather than the clock alone.
Common Mistakes to Avoid
Do not skip the soak. Dry bread cubes can remain firm in the middle.
Do not overfill the dish with raw spinach. Wilt it first to release excess moisture.
Do not pull the casserole while the center still jiggles like liquid.
Variations
Swap baby spinach for finely chopped kale, cooking it until tender first.
Use Monterey Jack made with microbial or vegetarian rennet in place of cheddar.
Add sautéed mushrooms, but cook off their liquid before layering.
What to Serve With It
Serve with Christmas salad for a fresh contrast or cranberry sauce on the side. Browse the recipe index for more holiday dishes.
Storage
Cool leftovers promptly, cover, and refrigerate for up to 3 days. Follow the USDA leftovers guidance when serving a brunch buffet.
Reheating
Cover individual portions and warm at 325°F until hot throughout, or microwave in short bursts. Avoid prolonged heat that dries the eggs.
Make Ahead
Assemble the pan, cover, and refrigerate up to 12 hours. Set it on the counter while the oven heats, then bake until fully set; a cold pan may need a few extra minutes.
For a shorter morning bake, set out the measured vegetables, bread, and cheese the evening before, then mix the custard and assemble the pan after dinner. Keep the covered dish on a level refrigerator shelf so the liquid settles evenly. Do not leave an egg casserole at room temperature overnight.
For smaller households, bake the full pan and refrigerate portions individually. They make a quick breakfast on the following days without repeating the prep work.
If the casserole has been chilled overnight in a glass dish, avoid moving the cold dish straight into a very hot oven. Let it sit briefly while the oven heats, following the dish manufacturer’s guidance. Keep the total time out of the refrigerator short. Bake on the center rack so heat reaches the middle evenly, and slice only after the 10-minute rest so the bread and eggs hold their shape.
FAQs
Can I make Christmas morning breakfast casserole the night before?
Yes. Cover the assembled pan and refrigerate up to 12 hours, then bake it in the morning.
What bread works best?
A sturdy day-old sandwich loaf or French bread holds its shape after soaking.
How do I know the eggs are cooked?
The center should be set with no liquid egg, and a knife inserted near the middle should come out clean.

