Adding the spinach toward the end of cooking retains its vibrant green color. Throw in some thawed frozen peas and/or some cooked asparagus, too, if you want an extra boost of green veggie power. —mrslarkin
In a medium-sized pot over medium heat, melt the butter. Add onions and cook until translucent. Do not brown the onions.
Add the rice and stir to coat the grains with the butter/onion mixture.
In half-cup increments, ladle the hot broth over the rice and stir, until most of the broth is absorbed. Continue this step until all the broth is absorbed, and rice is al dente, and still a little soupy.
Taste the rice for salt and if needed, add some to the pot.
Add the cheese, the nutmeg, and stir. Turn off the heat. Add the spinach, a handful at a time, and quickly fold into the risotto. Stir in the cream or butter.
Serve in warm bowls topped with some more Parmigiano, and some cracked black pepper, if desired.