Sourdough breakfast casserole is the perfect recipe for a weekend brunch or delicious meal when you want to use up some day-old sourdough bread. Savory and packed full of delicious breakfast flavors, this sourdough breakfast casserole is full of sourdough bread, eggs, vegetables, cheese and breakfast sausage. It's filling and absolutely delicious - perfect for a sourdough baker to serve to a crowd!
2bell pepperschopped (red, yellow and orange peppers work best)
1sweet onionchopped or diced (small or medium size onion)
3clovesgarlic, minced
10largeeggs
2cupswhole milk2% also works well
1teaspoonmustard powder
1teaspoonsalt
½teaspoonpepper
1cupParmesan cheeseshredded
1cupGruyere cheeseshredded, see recipe notes on cheese
1-2Tablespoonsolive oilto sauté vegetables if needed
1Tablespoonunsalted butter, softenedfor the pan
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Instructions
Prepare a 9 by 13 casserole dish by buttering the pan. Add cubed sourdough bread to the buttered pan.
Cook 1 lb of breakfast sausage in a skillet over medium heat until browned and cooked all the way through. Reserve some of the grease to use in cooking the vegetables and pour cooked breakfast sausage evenly over the cubed sourdough bread.
While the sausage is cooking, prepare the vegetables by slicing and dicing peppers, onion and garlic. Pour a little of the grease from the sausage into the same frying pan and sauté peppers and onions over medium-low heat for about 5-10 minutes until softened. Add the garlic and a pinch of salt and pepper to the pan and sauté another few minutes until fragrant. Pour the vegetables on top of the sausage in the casserole dish.
Shred the Gruyere and Parmesan cheeses and sprinkle on top of the vegetables, covering the entire casserole dish.
To a medium-sized bowl, whisk together eggs, milk, mustard powder, salt and pepper until combined. Pour evenly over the top of the casserole. Cover with aluminium foil and stick in the refrigerator for one hour or overnight (12-16 hours).
Before baking the breakfast casserole, pre-heat the oven to 350ºF. Place the casserole in the oven and bake for 20 minutes with the aluminum foil covering the casserole. After 20 minutes, take the cover off the casserole and bake for another 30-35 minutes until puffed up, browned and baked all the way through. Let cool for about 5 minutes and serve. Enjoy!
Notes
Cheese: We love this sourdough breakfast casserole with Gruyere cheese, but you can substitute any cheese that you prefer. Other good options: fontina, sharp cheddar, pepperjack or any favorite cheese.Variations: You can add any vegetables you like to this sourdough breakfast casserole. I like adding mushrooms, spinach and even tomatoes. 1-2 cups more of sautéed vegetables can be added that have been cooked down or you can replace the vegetables in this casserole with ones that you prefer.Sourdough Bread:This is the recipe I use for my sourdough bread. Whatever bread you choose to use, the bread should be completely cooled. I prefer using bread that is a day or two old in this recipe.