High Protein Spinach Casserole

Ingredients 3 10-ounce packages frozen spinach, thawed and pressed in mesh strainer to remove water 1 cup low-fat milk 1/4 cup all-purpose flour 1/4 teaspoon salt 1/4 teaspoon white or black pepper 1/8 teaspoon nutmeg 1 cup extra sharp Cheddar cheese, divided 1 cup...