1. Preheat oven to 350° and coat 13 x 9-inch pan with nonstick spray.
2. Pan fry the hash brown patties in a skillet according to packaging directions. Crumble the patties and evenly spread them into the 13 x 9-inch pan once fried.
3. Microwave the sausage patties for 40 seconds and then crumble them.
4. Evenly top the hash browns with the sliced spinach. Follow with the sausage and 2 1/2 cups cheddar cheese.
5. In a medium bowl, whisk together the eggs, half and half, salt and pepper. Pour over the casserole mix and pat down the mixture with a flat spatula.
6. Top evenly with the sliced tomatoes and sprinkle with remaining cheese and parsley flakes.
7. Bake 45 minutes. Serve hot or cold.