Wash the spinach, then place in a pan with just the water that clings to its leaves. Cover. Cook over low heat for 6-8 minutes or until wilted. Drain well and set aside.
Squeeze out as much liquid as possible then finely chop the spinach. A processor works well for this. Place the spinach in a bowl along with the ricotta cheese, half the Parmesan cheese, the eggs, nutmeg and season to taste with salt and pepper. Beat until thoroughly combined. Sift in the flour and lightly work it into the mixture, adding enough to make a workable mixture. Cover with plastic wrap and chill for 1 hour.
With floured hands, break off small pieces of the mixture and roll into walnut-size balls. Handle as little as possible, they are delicate. Lightly dust the gnocchi with flour.
Bring a large pan of salted water to the boiling point. Add the gnocchi and cook 2-3 minutes until they rise to the surface. Remove from pan and drain well.
Meanwhile, melt the butter for the herb mixture in a large, heavy-bottom skillet over low heat. Add the oregano and sage and cook, stirring, for 1 minute. Add the gnocchi and toss gently to coat. Transfer to serving dish and sprinkle with the remaining Parmesan cheese. Serve immediately.