1 pound fresh basil, stems removed
1 cup ricotta cheese
¾ cup all-purpose flour, divided
½ cup freshly grated Parmigiano-Reggiano
2 egg yolks, lightly beaten
¼ teaspoon freshly grated nutmeg
2 teaspoons freshly ground white pepper
2 teaspoons sea salt, or more to taste
½ lemon, juiced (Optional)
Bring 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.
Mix 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.
Dust your hands with remaining 1/4 cup flour and form gnudi mixture into small balls.
Bring a large pot of salted water to a boil. Add lemon juice. Boil gnudi in batches until they float to the top of the water, 3 to 4 minutes. Drain.