1Bring a large pot of salted water to a boil. Add basil and cook uncovered until just wilted, about 1 minute. Immerse in ice water for several minutes to stop the cooking process. Drain. Squeeze very dry and finely chop.
2Mix ricotta cheese, 1/2 cup flour, Parmigiano-Reggiano cheese, egg yolks, and nutmeg in a large bowl. Add basil, white pepper, and salt; mix until gnudi mixture is well-combined.