Tortellini Alfredo Spinach Casserole



19 oz. frozen cheese tortellini
10 oz. frozen chopped spinach
16 oz. baby bella mushrooms, cleaned and sliced
1½ cups Alfredo sauce
8 oz. sour cream
15 oz. ricotta cheese
1 teaspoon garlic, minced
1 egg, beaten
¼ cup Parmesan cheese, shredded
1 tablespoon parsley, chopped
Salt and pepper to taste
1½ cups mozzarella cheese, shredded