First, wash and wilt your fresh spinach, then finely chop it. Drain any excess liquid because too much moisture will make the gnudi too soft. Mix it with ricotta, egg, parmesan, bread crumbs, lemon zest, nutmeg, and salt.
Dust a baking sheet with semolina flour. Using a cookie scoop, portion the mixture onto the sheet. Lightly dust and roll each scoop into smooth balls with your hands, making sure none stick together.
Refrigerate the gnudi for at least 1 hour. I’ve found that resting allows the exterior to firm up slightly, which helps them hold their shape during cooking. Overnight resting can also intensify the flavor.
Bring a large pot of salted water to a gentle boil. Test one dumpling first; once it floats, let it cook for another minute. Remove with a slotted spoon and place on a lightly floured dish towel.
Melt butter in a pan and add chopped Calabrian chilies. Toss the cooked gnudi gently in the sauce for a glossy, flavorful finish. Serve immediately for the best texture.