Bring a large, wide pot of salted water to a simmer. (Salty like the ocean—in the words of Chef Anne Burrell.) Put the spinach in a large bowl and separate it with your hands. Add the ricotta, 3/4 cup parmesan, flour, eggs, 3/4 teaspoon kosher salt, 1/4 teaspoon pepper and nutmeg. Mix with a silicone spatula to form a slightly sticky dough; just until combined, don't over mix.

Spread a little flour (about 1/4 cup) on a large dinner plate. Have an extra small container of flour standing by for your hands and the plate, as needed. Scoop out heaping tablespoonfuls of the spinach-ricotta mixture and roll into about 24 loose balls, using floured hands; a medium cookie scoop makes 24 perfectly uniform balls. Gently roll the balls in the flour. Shake each ball gently in your hand to let excess flour fall through your fingers. Place prepared balls on a second large dinner plate, cover loosely with plastic wrap and refrigerate for at least 15 minutes to firm up the dough. This can be done the day before.

Bring the marinara sauce to a simmer in a small saucepan over low heat, stirring occasionally. Whisk in the butter. (if using) The butter makes the sauce silkier, but if you prefer to leave it out it will still be delicious.

Meanwhile, gently lower the dumplings into the simmering water—NOT vigorously boiling, (with a ladle or slotted spoon). Be careful not to overcrowd the pan—work in batches if necessary. Cook until they rise to the surface and are firm, about 5 - 7 minutes. Don't let the water boil too vigorously, or they will fall apart. Remove the dumplings with a slotted spoon, letting the water drain off, and transfer to a large casserole dish (preferably in a single layer). Drizzle with a little olive oil and gently toss to coat. Leave uncovered or partially covered or the steam will keep cooking them. Set aside until ready to serve; if necessary cover and microwave to reheat.

To serve: arrange 4 gnudi on each serving plate, top with desired amount of sauce, and sprinkle with the remaining 1/4 cup parmesan. Enjoy!