Cheesy spinach and mushroom breakfast casserole is easy to make, gluten free, meatless, and delicious for breakfast or brunch!
This cheesy spinach and mushroom breakfast casserole has been making an appearance at our house for breakfast and brunch for nearly 30 years. At first it started out as a “strata” which had chunks of white bread. After we started cutting back on gluten and bread in general, I figured out away to omit it from this recipe without affecting the taste. The result, little did I know at the time, was a low-carb, dish that is now something I make whenever we have guests stay over. (This post was originally published on December 29th, 2011 and has been updated to contain nutritional information. As an Amazon Affiliate, I may earn commission on qualifying purchases.)
What’s in a breakfast casserole?
Every good breakfast casserole starts with a base of eggs. But from there you can add just about anything! This Spinach and Mushroom version is vegetarian, but I’ve also added diced ham or sausage. I make a another casserole with just Hatch chiles, that mimics Chile Rellenos (but without the carbs), for those who like it spicy! For the cheese, you can go crazy! Sharp cheddar is the perfect foil to the spinach and mushrooms. This Asparagus Mushroom Crustless Quiche looks a little fancier if you are having just a few people over. It’s delicious for lunch as well.
Can I make a breakfast casserole ahead of time?
There are two ways you can make this casserole ahead of time. First, you can prep the entire dish, cover and refrigerate it until the morning. Or you can make it and refrigerate it and then just re-heat the next morning. To re-heat, turn oven to 325 degrees F. Put covered casserole into the oven and heat until hot and bubbly, about 35 minutes.
Can I freeze this breakfast casserole?
Yes! Just cut into individual portions and wrap well. This is a great way to have a grab and go breakfast! Just defrost the night before in the refrigerator and heat until warm and bubbly in the microwave. This casserole will last about 6 months in the freezer.
Can I make this Cheesy Spinach and Mushroom recipe in muffin cups?
If you’re doing meal prep and you’d rather have smaller portions, you can certainly refer to this recipe for gluten free egg “muffins”, for adjusted cooking time and ingredient amounts. Again, feel free to use whatever vegetables and cheese you like.
To make the Spinach and Mushroom Casserole
Sauté onions and mushrooms, add spinach and wilt. Drain excess water from spinach mixture and chop.
Add spinach and mushrooms to egg mixture.
Pour into a baking dish and smooth. If planning on refrigerating to bake later, wrap well in foil. It is now ready to bake. Add an additional 5-10 minutes to cooking time if baking from refrigerator.
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Spinach and Mushroom Breakfast Casserole
- Pre-heat oven to 350* F. Use 1 Tablespoon butter to grease 13" X 9" baking dish.
- Heat 4 Tablespoons butter in a large skillet or sauté pan, and sauté yellow onions and mushrooms, about 3-4 of minutes until onions are translucent and mushrooms are soft. Add garlic and sauté another minute.
- Add spinach, a handful at a time, and sauté. Cover skillet and let spinach wilt, about 5 minutes.
- Let cool, drain excess liquid, and chop more finely.
- In a separate bowl, whisk eggs, cottage cheese, cheddar cheese, green onions, and salt and pepper. Add cooked spinach and mushroom mixture.
- Mix well and pour into baking dish.
- Bake for 45-50 minutes or until top is golden brown and center is done.