Grease a 9 x 13 pan with nonstick cooking spray, set aside.
Add sausage to a large skillet and cook over medium high heat until fully cooked and no longer pink. Remove from the pan and set aside.
Add bell peppers, onions and mushrooms to the same pan and sauté until tender, 5-6 minutes.Add in spinach and cook until wilted, set aside.
Layer the bread in the prepared baking pan and top with sausage and bell pepper.
In a large bowl, whisk together eggs, cream and seasonings.
Pour egg mixture evenly over casserole. Sprinkle with cheese.Refrigerate overnight or bake immediately.
When your ready to eat preheat the oven to 350 degrees.Bake uncovered for 50-55 minutes or until the eggs look set.Serve immediately with green onions, if desired.
Notes
Make ahead instructions:Assemble as directed and store in the fridge for up to 24 hours. When you are ready to bake allow the casserole to come to room temperature while the oven preheats and bake as directed. You may have to add an additional 5 minutes on to the cooking time.Reheat Instructions: This reheats really well and keeps in the fridge for up to 4 days! You can freeze for longer in individual portions if desired!