In a medium saucepan, combine the frozen spinach and 2 tablespoons of water. Cover and cook over low heat, stirring occasionally, until the spinach is completely thawed, about 15 minutes.
Drain the spinach in a strainer and allow to cool.
Place the spinach on a clean dish towel or cloth napkin, then grab the corners to form a pouch. Twist to squeeze out as much liquid as possible, then set aside.
Beat the eggs in a large bowl.
Add the bread crumbs, Italian seasoning, ricotta, Parmesan, scallions, parsley, basil, garlic, nutmeg, and black pepper. Mix well. Add the spinach and mix again until the spinach is well-incorporated.
Cover and refrigerate for 24 hours.
Line two baking sheets with parchment paper. Lightly dust with flour.
Take a generous teaspoonful of the chilled dough, roll it into a ball, then place on the prepared baking sheet. Repeat with remaining dough, making sure the dumplings don’t touch.
Make a dent in the middle of each dumpling with the end of a wooden spoon or your thumb.
Select a saucepan that will fit a bamboo steamer. Fill it half-full with water and bring to a boil.
Place the dumplings in a steamer basket, making sure they don’t touch.
Place the basket on top of the saucepan and steam over high heat for 10 minutes.
Transfer the dumplings to a covered dish to stay warm while you steam the remaining dumplings.