Spray a 9x13 baking dish with non stick cooking spray.
Microwave your frozen hash browns for 10 minutes on high.
In a frying pan, break up and brown the the sausage over medium high heat until crumbled and cooked through then set aside.
In a large mixing bowl, whisk together the eggs and half and half, then set aside.
Place the microwaved hash browns in the prepared 9x13 pan. Drizzle the melted butter over the top, then sprinkle the herbs de provence, onion powder, salt and pepper all over the potatoes. Toss well until everything is evenly coated, then spread out evenly in the pan.
Sprinkle the shredded sharp cheddar, mozzarella and parmesan cheese over the top.
Sprinkle the cooked sausage bits over the cheese and use a fork to toss it all together just a bit.
Pour the egg mixture evenly over the top of the casserole.
Bake at 350 for 45-55 minutes until it is nice and golden brown, has no jiggle in the middle and it's just starting to crisp around the edges!
Remove from oven and let sit for 10 minutes before serving. (Garnish with chopped fresh parsley if desired.)