Make-Ahead Gluten Free Breakfast Casserole (Overnight Egg Bake!)

Introduction

Christmas morning should be magical, not messy. But for those managing a gluten intolerance, finding a safe, satisfying, and delicious holiday brunch recipe can be a headache. This year, simplify your holiday and guarantee a delicious meal with the Gluten Free Make-Ahead Christmas Breakfast Casserole.

Prep this simple, hearty egg bake tonight, and wake up to a stress-free meal tomorrow.

Allergen Information:

This recipe is certified Gluten-Free when using labeled ingredients. It can easily be made Dairy-Free by swapping regular milk for plain oat or soy milk and using a certified dairy-free cheese alternative. Always check the labels on breakfast meats and spice blends for hidden gluten.

Ingredient Notes:

Base & Custard

Gluten-Free Bread – I recommend using a sturdy, dense GF loaf (like Italian or sourdough-style). Day-old bread is best. The type of GF bread you use is critical for texture; using soft sandwich bread may result in a mushy casserole.

Eggs – Use size large. These are the primary binder and protein source for the casserole.

Milk – You can use regular whole milk for a rich custard, or plant-based milk (like oat, cashew, or soy) for a Dairy-Free option. I made several test batches successfully with a dairy-free almond/cashew blend.

Salt, Pepper, Dried Sage, Garlic Powder – These spices provide the essential savory, holiday-appropriate flavor profile.

Filling

Breakfast Sausage – Use bulk breakfast sausage. Ensure the packaging explicitly states it is Certified Gluten-Free, as some brands use wheat fillers or binders. You can substitute this with diced GF ham or bacon.

Shredded Sharp Cheddar Cheese – I recommend sharp cheddar for flavor, but Monterey Jack works well too. If you are Dairy-Free, use a high-quality plant-based cheese shred that melts well.

Red Bell Pepper (Optional) – Adds nice color and a subtle sweet crunch to the savory filling.

Tips For Success

Toast for Structure: Lightly toast the GF bread cubes for about 10 minutes at 300F 150celcius. This gives them the structural integrity to hold up during the overnight soak.
Drain the Meat: After cooking the sausage, drain all the grease thoroughly. Excess fat will pool at the bottom of your casserole dish.
Cover Tightly: Ensure the dish is tightly covered with plastic wrap during the refrigeration period to lock in moisture.

Step-By-Step Photos and Directions:

Here is a visual guide to ensure your Gluten-Free Make-Ahead Breakfast Casserole turns out perfectly moist and golden brown.

Prep the Base: Dice your sturdy GF bread into 1-inch cubes. Lightly toast them on a baking sheet at 300F 150 for 8-10 minutes. This is key for structure! Place the cubes in a greased 9×13-inch baking dish.

Cook the Filling: Brown the certified GF breakfast sausage in a skillet. Once cooked, drain all the grease completely. Scatter the sausage, the red bell pepper (if using), and 1 cup of the shredded cheese evenly over the bread cubes.

Mix the Custard: In a large bowl, whisk together the eggs, milk (dairy or non-dairy), salt, pepper, garlic powder, and sage until everything is fully combined and the mixture is slightly frothy.

Soak: Slowly pour the entire egg mixture over the bread and meat layers. Gently press down on the bread cubes with a spatula to ensure every piece is completely saturated.
Chill (Overnight): Cover the dish tightly with plastic wrap. Place the casserole in the refrigerator for a minimum of 8 hours, and ideally 12 hours (overnight). Do not skip this step!

Bake: The next morning, preheat your oven to 350C. Remove the plastic wrap and sprinkle the remaining 1/2cup of cheese over the top. Bake for 45–55 minutes. The center should be set, and the top golden brown.
Rest and Serve: Let the casserole rest on the counter for 10 minutes before slicing and serving. Garnish with fresh chives or parsley. Enjoy your stress-free holiday breakfast!

Frequently Asked Questions:

Can I freeze this casserole? Yes. You can freeze it unbaked or fully baked. Wrap tightly in foil and plastic wrap. Thaw overnight in the fridge before baking or reheating.
Can I make this vegetarian? Absolutely! Omit the meat and add 1 cup of sautéed vegetables like spinach, mushrooms, or caramelized onions to the filling.

Casserole Troubleshooting:

Why is my casserole dry?

The bread did not fully soak up the egg mixture. Ensure you chill for the full 8-12 hours, and gently press the bread cubes down before covering and refrigerating.

Why is the center still runny?

The casserole needs more time. Cover the top with foil if it’s browning too fast and continue baking until the center is set (a knife inserted near the center should come out clean).

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The Best Gluten Free Make-Ahead Breakfast Casserole

Equipment

9×13-inch baking dish
Large mixing bowl
Whisk
Skillet (for cooking meat)