Holiday Breakfast Casserole

I made this for Christmas morning and it was a hit. Especially the sausage that's cooked with delicious ground fennel. This is the perfect make-ahead casserole so you can enjoy those early morning gatherings and have something delicious to soak up those mimosas or Bloody Marys.

Ingredients

• 4 cups cubes of day old crusty bread (you want the bread a bit hard) or frozen diced potatoes
• 2 teaspoons neutral oil
• 1 1/2 pounds ground pork sausage, casings removed
• 1-2 teaspoon dried rosemary or Italian seasoning, optional
• 1-2 teaspoon ground fennel (you can also use fennel seed)
• red pepper flakes (optional)
• 3/4 cup chopped yellow onion (1/2 of a large onion)
• 2 garlic cloves, minced
• 2 cups chopped yellow or orange bell peppers
• 1 cupsliced mushrooms
• 1 cup roughly chopped fresh spinach
• 12 large eggs
• 1/4 teaspoon salt
• 1/8 teaspoon freshly ground black pepper
• 2/3 cup whole milk 
• 1 cup shredded cheddar cheese
• optional garnish: green onion and/or chopped cilantro

Instructions

1. Grease a 9×13-inch. Arrange bread cubes in an even layer in bottom of pan.
2. Heat olive oil in a large skillet over medium heat. Add sausage and rosemary/Italian, red pepper flakes (if using) and ground fennel seasoning and break up the sausage into bite-size pieces with a wooden spoon or rubber spatula. When the sausage has cooked throughly, remove the sausage to a bowl and set aside.
3. To the same skillet, do not remove the fat from the sausage. Add the onion, garlic, peppers, mushrooms, and spinach and cook until everything has slightly softened. Add the sausage into the vegtable mixture and mix well.
4. Remove sausage and vegetable mixture from heat and spread in an even layer on top of bread or hash browns.
5. Whisk the eggs, salt, pepper, milk, and cheese together. Evenly pour over sausage/vegetable mixture. Add another sprinkle of salt and pepper on top.
6. Cover casserole with plastic wrap or aluminum foil and refrigerate for at least 30 minutes and up to 24 hours. (When ready to bake, allow to sit at room temperature for 10–15 minutes as oven preheats.)
7. Preheat the oven to 375°F. Bake the casserole, uncovered, until the top is golden, edges are crisp, and a toothpick inserted in the center comes out clean, about 40–45 minutes.
8. Cool for 10 minutes, then slice and serve.
9. Leftovers keep well in the refrigerator for up to 5 days. Reheat in the microwave to your liking.