Sausage and Egg Brunch Casserole

1 pound spicy Italian pork sausage
2 oz. olive oil
1 medium onion, diced
1 pound of mushrooms, sliced
1 tablespoon Worcestershire sauce
1 tablespoon apple cider vinegar
1/2 teaspoon cayenne powder
1/2 teaspoon garlic powder
1 teaspoon Italian seasoning
1 package frozen spinach (10 oz.), thawed and well drained
1 stick of butter, melted
1 cup shredded cheese
1/4 cup all purpose flour
1 teaspoon baking powder
1 dozen eggs, lightly beaten
1/4 cup dried parsley
salt and pepper to taste

• Preheat oven to 400°F. Spray a 9 x 13 casserole with nonstick cooking spray.

• Brown sausage. Transfer to a plate.

• In a large skillet, cook diced onion in oil until soft. Add mushrooms, Worcestershire sauce, vinegar, cayenne, garlic, and Italian seasoning. Mix well and cook for several more minutes. Add drained spinach and cook for a few additional minutes.

• In a large mixing bowl, combine butter, cheese, flour, and baking powder. Whisk eggs and add to mixture. Stir in cooked sausage, vegetables, and parsley. Season with salt and pepper. Mix well.

• Pour into a prepared pan and bake for 35 minutes or until browned and set in the middle. Let rest 10 minutes before serving.

Adapted from Dorothy Kern's Cheesy Sausage Egg Casserole at Crazy for Crust.