Preheat oven to 350 degrees. Over medium high heat, place spinach in a large skillet and pour in 1/2 cup of water. Cover and steam until wilted. Drain spinach and reserve.
In a medium bowl, Stir together bread crumbs., 1/4 cup Parmesan and butter. Press crumb mixture into even layer in a 9 inch pie plate and chill for 15 minutes.
In a large bowl, beat together the eggs, ricotta cheese, sour cream, 1/2 cup Parmesan, basil, nutmeg and salt and pepper. Stir in the spinach and mix until well combined. Pour into chilled crust. Top with remaining Parmesan and bake for 45 minutes or until firm. Cool to room temperature before serving.