Wash and stem the spinach. Wilt the spinach by either blanching or using the microwave. If blanching place spinach in a large pot of salted boiling water. Cook for about 30 seconds. Remove and place in an ice bath to stop the cooking. Remove to a dish towel and squeeze out as much liquid as possible. If using the microwave; cook in batches 30 seconds at a time until wilted. Let cool and using your hands squeeze out as much liquid as possible. Chop finely.
Heat 2 Tbsp. Olive Oil in a skillet over medium heat. Add the shallot and cook until just browned; 3 to 5 minutes. Add the chopped spinach. Remove from the heat to a bowl. Let cool slightly.
When the Ricotta has lost most of its liquid remove from the oven and let cool slightly.
Add the baked ricotta, egg yolks, flour, and parmesan to the spinach shallot mixture. Mix until well combined. Add the nutmeg, salt and pepper. Adjust seasoning accordingly.
Form into 1 to 1 1/2 inch balls. If the mixture is too loose, add a little more flour.
Fill a large pot with water. Add 1 tsp. salt and bring to a boil.
Meanwhile melt the butter in a small skillet and cook until browned; about 4 to 5 minutes.
Cook the gnocchi in the boiling water until they float to the surface; about 4 minutes. Drain and let cool slightly as this helps firm them up.
Toss them into the browned butter being careful not to crowd, as they are still soft and delicate. Brown on all sides.
Serve on a bed of the tomato sauce and top with freshly grated parmesan cheese.