This delicious low carb breakfast casserole combines the traditional eggs, sausage, and cheese with oven roasted broccoli, mushrooms and bell peppers. Your family will not miss the carbs in this tasty and filling breakfast dish that is gluten free, soy free and refined sugar free!

Breakfast casserole, but make it low carb.
The idea for this recipe actually came about when my family friend Diane Gainey asked me to help her out with cooking for guests she had coming to town. She requested a breakfast casserole without any potatoes or bread, which, honestly I had never had before.
Rather than attempt to "replace" the potatoes with cauliflower rice or something of that nature, I ended up roasting some broccoli, mushrooms and bell pepper and adding them to the mix. And I'll tell you what, it turned out fantastic!
The roasting of the vegetables is an extra step but I can assure you it is worth it!
This breakfast casserole packs a huge punch of flavor and a ton of protein. It will definitely keep you full for a while!
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Roasting the Vegetables
Roasting the vegetables not only adds a great depth of flavor but it also removes moisture which could affect the casserole's consistency.
I recommend starting with fresh, not frozen, vegetables and roasting at 400 degrees for 20-25 minutes.
Is this recipe Keto?
This recipe recipe is very low carb and decently high in fat, which would make it compatible with most standard Keto diets.
If you want to increase the fat content simply replace the half and half with full cream.
Check out other Low Carb Recipes from The Jam Jar Kitchen!
Low Carb Chicken Panang Curry "Noodle" Soup
Steak Salad with Deviled Eggs and Lemon Horseradish Vinaigrette
Sheet Pan Brats and Fall Veggies

Equipment needed for this Low Carb Breakfast Casserole
- 9x9 inch casserole dish: Or a dish with comparable measurements. I used this Le Creuset Stoneware Rectangular Dish, 1.8 qt. (10.5" x 7").
- Skillet and firm spatula: For cooking the sausage and onions
- Paper towel lined plate: For cooling the cooked sausage and onions.
- Measuring cups and spoons
- Cutting board and knife
- Baking sheet: You can line with foil for easier clean up if desired.
- Large mixing bowl
- Whisk or fork
- Cheese Grater: I love this Oxo Good Grips Box Grater.
Ingredients
- Breakfast sausage: Your favorite brand will work and you can buy it ground or in patties. If you purchase patties just be sure to break them up during the cooking process.
- Onion: I like yellow but white or red would also work.
- Olive oil
- Mushrooms: I usually quarter mine, or cut them in ⅙ths is the mushrooms are especially large.
- Broccoli florets: You definitely want to use fresh, not frozen, for this recipe.
- Bell Pepper: Red, orange or yellow work best. Green would also work but it's less sweet and flavorful in my opinion.
- Cheddar cheese: Personally I like buying a block of cheese and then shredding myself. I think freshly shredded cheese just has a better consistency. But you can definitely use pre-shredded cheese in a pinch. You can also substitute cheddar with Monterey Jack or your favorite hard cheese.
- Eggs
- Half and half: You can substitute this with ½ cup heavy cream and ½ cup milk. Or to increase the fat content for Keto simply replace with full fat cream.
- Pinch of cayenne (optional)
- Salt & pepper
Step-by-Step Instructions
Time needed: 1 hour and 20 minutes.
How to make this Low Carb Breakfast Casserole with Sausage and Roasted Vegetables
- Preheat the oven and prepare the vegetables.
- Roast the vegetables.
- While the vegetables roast, brown the sausage.
- Cook the onions.
- Cool the sausage and onions.
- Grate the cheese.
- Preheat the oven and make the egg filling.
- Add sausage, cheese and vegetables to the casserole dish.
- Pour in the egg mixture.
- Sprinkle with cheese and bake.
- Remove from oven, rest and enjoy!

Can I make this in advance?
Yes! This casserole is wonderful made in advance.
If you are planning to make it a day or two before serving simply store in the fridge. When you're ready to serve bake at 375 degrees for around 15-20 minutes until heated through.
Can I substitute other vegetables?
You certainly can! Zucchini, carrots and cauliflower would also work well in this recipe.
Like this recipe? Let me know in the comments!
Recipe

Low Carb Breakfast Casserole with Roast Vegetables
Ingredients
- 8 oz mushrooms, quartered
- 2 cups fresh broccoli florets
- 1 large bell pepper, cut in a medium/large dice
- olive oil
- 1.5 lb breakfast sausage, ground or patties
- 1 small onion, halved, quartered and thinly sliced
- 8 oz cheddar cheese, shredded and divided into 2 equal potions substitute with Monterey jack or pre-shredded cheese if desired
- 10 eggs
- 1 cup half and half substitute with ½ cup milk and ½ cup cream
- 1 tsp salt
- 1 tsp black pepper
- pinch of cayenne
Instructions
- Preheat the oven to 400 degrees F. Drizzle a little olive oil on a baking sheet and arrange broccoli, mushrooms and bell pepper. Drizzle a little more olive oil over the top of the vegetables along with a sprinkle of salt and pepper. Roast at 400 degrees fro 20-25 minutes until the veggies are cooked and lightly browned, but still al dente. Remove from the oven and set aside to cool completely before adding to the casserole.
- While the vegetables are roasting cook the sausage and onion. Heat a skillet over medium high heat and add breakfast sausage to the pan, using a spatula to break up any large pieces. Cook until sausage is browned and cooked through. Then remove sausage to a paper towel lined plate to cool.
- In the same pan you cooked the sausage in, add a drizzle of olive oil and the sliced onions. Cook over medium to medium high heat for about 5 minutes until the onions are golden and cooked through, making sure to scrap up the brown bits at the bottom of the pan. Remove to a paper towel lined plate or bowl to cool. Grate the cheese (if not using pre-shredded) and set aside.
- Preheat the oven to 375 degrees F. In a large mixing bowl whisk together eggs, half and half, 1 tsp salt, 1 tsp pepper and a pinch of cayenne until well combined. Prepare a 9x9 baking dish with a little olive oil or cooking spray.
- Once the vegetables and sausage are cool to the touch combine them and add ½ of the cheese. Mix to combine then add the mixture to the prepared casserole dish, spreading to cover evenly. Pour the egg mixture over the sausage and vegetables. Then sprinkle the remaining cheese on top of the casserole.
- Bake the casserole at 375 degrees F for approximately 35 minutes until lightly browned and the center no longer jiggles. Remove from the oven and allow to rest at least 15 minutes before serving. Enjoy!
Nutrition

This is such a delicious way to start the day!
Love the flavours - roast vegetables is such a fantastic addition.
I love everything about this! I’m a sucker for any casserole with loads of cheese, and those roasted vegetables add such nice flavor.
I love a good breakfast casserole but they can be so heavy. With the roasted vegetables this tastes great and is also a great start to the day!
Wow this looks amazing! I am going to make this for my family this weekend. I am always looking for a good weekend breakfast.
This was so easy and delicious! Definitely making it again this weekend!
What a great way to use up all of my veggies! I love this recipe. Perfect for the mornings!
This looks like the best breakfast casserole ever! Can't wait to make this tomorrow!
I love this healthy and delicious breakfast casserole! I would eat this even if I wasn't watching my carbs - so good!
This casserole was so satisfying and delicious and no one could tell that it was low carb! We actually made this for dinner tonight as part of a "breakfast for dinner" spread and it turned out great!
This is a crowd pleaser recipe! Perfect for a brunch party! It disappears!