Grease a 1-1/2-quart casserole; set aside. In a large bowl, combine cottage cheese, spinach, feta cheese, eggs, butter, flour, onion, and nutmeg; mix well. Transfer mixture to the prepared casserole. Bake, uncovered, in a 350 degree F oven about 45 minutes or until center is almost set (an instant-read thermometer inserted in center should register 160 degrees F). Makes 8 side-dish servings.