’Twas the Night Before Christmas Breakfast Casserole
Christmas morning has a way of making even simple meals feel rushed. This breakfast casserole was designed to remove that pressure without relying on shortcuts or overly processed ingredients.
It’s built around roasted potatoes instead of bread, a properly seasoned egg custard, and vegetables cooked just enough to hold their texture. Everything is cooked first, allowed to cool, then assembled and rested so the final bake is even and clean.
This is the kind of breakfast that feels special without being complicated.
Ingredient choices that matter
Breakfast sausage
When possible, I choose a breakfast sausage made without fillers, MSG, or gluten. You don’t need anything fancy here, just a clean ingredient list. Sausage carries most of the seasoning in this dish, and using a well-made one makes a noticeable difference in flavor and texture.
Fresh spinach vs pre-washed boxed greens
I use fresh spinach here instead of pre-washed boxed greens. Many bagged greens are treated with antimicrobial sprays, sometimes irradiated, and designed for long shelf life rather than freshness. Even when labeled “triple washed,” they can carry residues from processing that fresh bunch spinach simply doesn’t.
Starting with whole spinach lets you control what goes into the dish. You wash it yourself, cook it briefly, and avoid unnecessary treatments that don’t add anything nutritionally or culinarily. In a simple recipe like this, ingredient quality matters, and fresh spinach keeps the casserole cleaner and more intentional.
Make-ahead and same-day options
This casserole is written as an overnight bake, which allows the custard to hydrate and settle into the ingredients. That said, it can be baked the same day if needed.
If baking right away, let the assembled casserole rest at room temperature for 15–20 minutes before baking. This step helps prevent uneven cooking and improves texture.
Why this works for holiday mornings
Everything is cooked before assembly, so there are no surprises
The casserole bakes evenly and slices cleanly
It feeds a group without requiring last-minute prep
Leftovers reheat well for the days after Christmas
This is a practical recipe, but it’s also intentional. Simple ingredients, treated correctly, and assembled with care.
Twas the Night Before Christmas Breakfast Casserole
Ingredients
Potato Base
- 2 medium russet potatoes, peeled & diced
- 1 tsp avocado oil or olive oil
- 1/2 tsp kosher salt
- Pinchfreshly ground pepper
Filling
- 1 pound breakfast sausage
- 1 tbsp butter, if needed
- 1 red bell pepper, diced
- 1 small onion, diced
- 2 cups fresh spinach, chopped
- 1½-2 cups shredded cheese (cheddar, mozzarella, or Italian blend)
Custard
- 10 large eggs
- 1 cup plain Greek yogurt
- 1/2 cup milk
- 1 tbsp Italian seasoning
- 1½ tsp kosher salt
- 1/4 tsp white pepper
Instructions
- Roast the potatoesPreheat oven to 425°F.Toss diced potatoes with 1 teaspoon oil, salt, and pepper.Roast 15–20 minutes, just until tender, not browned.Set aside to cool.Cook the sausageBrown sausage in a skillet until fully cooked.Remove sausage from the pan and set aside.Leave the fat in the pan, add 1 tablespoon butter only if needed.Cook the vegetablesAdd onion and red bell pepper to the pan.Cook about 5 minutes, just until softened.Add spinach and cook 1–2 minutes, just until wilted.Remove from heat.Cool before assemblingAllow the potatoes, sausage, and vegetables to cool slightly.Make the custardIn a large bowl, combine eggs, Greek yogurt, milk, Italian seasoning, kosher salt, white pepper, and nutmeg.Mix until smooth, by hand or with a hand mixer.AssembleButter a 9×13-inch baking dish.Spread cooled potatoes evenly on the bottom.Sprinkle sausage over the potatoes.Add the vegetable mixture, then top with shredded cheese.Pour custard evenly over the casserole.Chill overnightCover tightly and refrigerate 8–12 hours.Rest before bakingRemove casserole from the refrigerator and let sit at room temperature for 15–20 minutes.BakeBake uncovered at 350°F for 45–60 minutes, until the center is set.Rest and serveLet rest 10–15 minutes before slicing.
Note
- This casserole can be baked immediately after assembly. The overnight rest improves texture, but is not required.