This Spicy Sausage and Caramelized Onion Breakfast Casserole is one of my favorite low carb/keto breakfasts. The sweet, deeply flavored caramelized onions are what elevate this hearty, savory casserole.
I enjoy finding new ways to prepare eggs for low carb breakfasts. Even if I love eggs, variety keeps breakfast interesting. Casseroles are especially convenient because they make several servings at once and reheat well throughout the week.
This casserole stores and reheats nicely for at least three days. It delivers the elements a great breakfast casserole should: well-seasoned spicy sausage, melty cheese, savory mushrooms and the sweet contrast of caramelized onions. Every bite offers layered flavors and satisfying texture. While caramelizing onions takes a bit of time and gentle heat, the payoff is worth it — they become sweet and rich and really shine in this dish.
Tips for making Spicy Sausage and Caramelized Onion Breakfast Casserole:
- To save time, caramelize the onions a day ahead and refrigerate them.
- Use plain breakfast sausage if you prefer a milder, non-spicy version.
- Swap Colby Jack for cheddar or Swiss to change the flavor profile.
- Cook onions over low heat and stir occasionally to avoid burning and to develop sweetness.
More Low Carb Breakfasts
- Low Carb Sausage Breakfast Casserole
- Air Fryer Low Carb Bacon, Egg, and Cheese Roll-ups
- Bacon and Egg Cups
Spicy Sausage and Caramelized Onion Breakfast Casserole
This Spicy Sausage and Caramelized Onion Breakfast Casserole is a flavorful low carb/keto breakfast option. The caramelized onions add a touch of sweetness that balances the spicy sausage.
Breakfast
American
keto, low carb, low carb breakfast casserole
20
minutes
40
minutes
1
hour
9
444
kcal
Ingredients
- 3 tablespoons butter
- 1 large sweet onion, diced
- 1 pound spicy breakfast sausage
- 1 (8-ounce) package white mushrooms, sliced
- 10 large eggs
- 3/4 cup heavy cream
- 1 1/2 cups shredded Colby Jack cheese
- 1/2 teaspoon garlic powder
- 1/2 teaspoon salt
- 1/4 teaspoon pepper
Instructions
-
Melt butter in a large skillet over medium-low heat. Add the diced onion and cook, stirring occasionally, until golden and deeply caramelized, about 15 minutes. Remove from heat and let cool slightly.
-
In a second large skillet, cook and crumble the sausage. When the sausage is about halfway done, add the sliced mushrooms and continue cooking until the sausage is no longer pink and the mushrooms are golden. Remove from heat and let cool slightly.
-
In a large bowl, whisk together the eggs and heavy cream. Stir in the shredded cheese, garlic powder, salt, and pepper until combined.
-
Transfer the cooked sausage, mushrooms, and caramelized onions into a greased 7×11-inch baking pan. Pour the egg and cheese mixture evenly over the top.
-
Bake in a 350°F (175°C) oven for 40 minutes, or until the casserole is set and the top is lightly golden. Allow to rest a few minutes before slicing and serving.
Nutritional info is provided as a guide only and can vary based on products and cooking methods used.
