This is a traditional recipe from the small towns that surround the city of Parma. Tortelli d'erbetta features delicate bites of fresh pasta, filled with ricotta and whatever greens you happen to have on hand. The joke about tortelli d'erbetta is that every town has a slightly different filling, and locals will order this dish at a restaurant just so that they can decry "my version is better!"
All versions will have a ricotta filling, and then some combination of cooked greens and fresh herbs. My version of this recipe included chard, fresh marjoram, finely grated parmigiano cheese and fresh lemon juice. The ricotta is creamy, the lemon is bright and acidic, the marjoram is sharply herbal, and the parmigiano gives everything a savory depth.
Feel free to experiment with other ingredients - you can try fresh oregano or basil instead of the marjoram, and beet greens or turnip tops or kale instead of the chard. —Josh Cohen