Cook the spinach in salted water and boil it for a few minutes. Drain well and chop finely. Drain the ricotta and mix it with the spinach.
Add the egg, nutmeg, cheese, flour, black pepper, a pinch of salt and mix until it will become a fine and soft dough.
Sprinkle a tray with flour. Using 2 small spoons, drop 1 teaspoon-sized pieces of dough into the pie pan.
Shake the pan gently to cover the dough with flour. Gently roll the pieces of dough into oval or round shapes.
Bring a large saucepan of salted water to a simmer. In batches, carefully add the gnudi.
They should sink and then float to the top. As soon as they begin to float, drain it and place in a large serving bowl.
Serve it with brown butter and parmesan.