Peel potato, add to pot of salted simmering water, when cooked strain, let it dry out. Save water and blanch spinach for 5 minutes. Shock spinach in Ice bath. Squeeze out extra water. and blend until smooth.
Put potatoes through a ricer and or gently mash until there are no lumps, in a large mixing bowl add spinach puree, egg, ricotta, Parmesan, salt, nutmeg and flour, fold all until firm ball is formed.
Cover with plastic wrap and refrigerate for 1 hour. Dust your work space with flour and roll out your gnocchi dough into "Long Snakes". Cut that into 1 inch pieces.
Gently drop your gnocchi into salted simmering water.Gnocchi are ready when they float to the surface, take them out with a slotted spoon and shock them in salted Ice water. Remove gently and place them on a dry towel.