Soak bread in milk. Let stand to absorb. Sauté onion, garlic, and spinach until spinach is tender, about 4 to 6 minutes. Set aside to cool. Squeeze the milk from the soaked bread. Mix in a bowl with spinach mixture, ½ cup grated parmesan, ricotta, eggs, breadcrumbs, salt, pepper and nutmeg. Add flour a little at a time until you have soft, wet batter. Bring a large pot of salted water to a boil. Spoon one ounce dumplings into the water to cook. Boil 6-8 dumplings at a time for 4-5 minutes per batch. Remove to a lined pan to cool. Before serving, melt and slightly brown butter in a sauté pan. Sauté dumplings to brown, 3-4 minutes Top with remaining parmesan and serve.