In large skillet, cook sausage over medium-high heat, stirring frequently until thoroughly cooked and no longer pink.
In large bowl, whisk together eggs, milk, and salt until thoroughly combined.
Evenly distribute half the bread into the prepared casserole dish. Sprinkle with half the cheese, half the black pepper, half the red pepper, and half the sausage. Repeat layers.
Pour egg mixture evenly over casserole.
Cover and refrigerate overnight, or bake immediately.
When you're ready to bake the casserole, preheat oven to 325°F. Bake uncovered for 60-75 minutes, or until eggs are set. If the top begins to brown too quickly, loosely cover the casserole dish with foil.
If desired, sprinkle the casserole with sliced green onions. Serve warm.
Notes
I typically use mild pork breakfast sausage in this recipe, but feel free to use any pork sausage you like. Try using a hot/spicy pork sausage for a spicy twist!You can use any bread you like in this casserole, although a sourdough sandwich loaf is my personal favorite. I like to toast my bread before incorporating it into the casserole, but this step is optional.