Set a large saucepot and a large skillet on the stovetop. Also set out a large mixing bowl and a medium mixing bowl.
Chop the baby spinach and place it in the medium bowl. Add the salt and toss. Then allow the spinach to rest and sweat off its moisture for at least 15 minutes.
Heat the saucepot over medium heat. Add the butter and onion wedges. Sauté the onions for 3-5 minutes, then pour in the tomato sauce. Turn the heat to medium low, partially cover, and simmer the sauce for 20 minutes. Then turn off the heat and allow the sauce to rest.
Meanwhile, in the larger bowl, combine the ricotta cheese, parmesan cheese, semolina flour, egg and extra egg yolk, chopped basil, garlic powder, and nutmeg. Mix well.
Once the spinach looks like it has wilted down. Poor off the juices. Move the spinach to a large paper towel and squeeze out the rest of the moisture. Then mix the chopped spinach into the ricotta dumpling mixture.
Move the dumpling mixture to a clean work surface. Press into an even rectangle, ½ inch thick. Then use a sharp knife to cut the dumpling mixture into one by 1 x 1 ½ inch pieces.
Pour 1 tablespoon of oil into the large skillet. Heat the skillet over medium. Once the oil is hot, move half the dumplings to the skillet. Fry for 1-2 minutes per side until the crust is golden brown. If needed, lower the heat to medium-low.
Move the cooked dumplings to a holding plate, then repeat with the remaining olive oil and dumplings.
Once all the dumplings are cooked, use a slotted spoon to remove the large onion chunks from the tomato sauce.
To Plate: Spoon tomato sauce into the bottom of a shallow bowl. Top with 8-10 Malfatti dumplings. Serve warm, sprinkled with extra Parmesan cheese if desired
Notes
You can make Malfatti balls if you like. They will just take longer to cook, with more rotating in the skillet. Approximately 6-8 minutes per batch.Homemade ricotta dumplings will keep well for up to 4 days in the refrigerator. Store in an airtight container and keep in the refrigerator. To reheat, lightly pan fry again in a bit of oil until warm throughout.