Place ricotta into fine mesh strainer and allow any liquid to drain off.
In a large skillet, add spinach with a sprinkle of water and salt over medium heat. Cook covered until wilted, using tongs to turn a couple times during cooking. Drain in a colander until cooled. Place cooked spinach in a clean cotton dish towel and completely wring out all liquid. Finely chop spinach.
In a bowl, combine drained ricotta and spinach with egg, parmesan cheese, flour, semolina, salt and nutmeg. Mix until evenly incorporated. Roll into 1 1/2" balls.
Bring a pot of salted water to boil. Cook Malfatti in batches in boiling water until they float, about 2-3 minutes.