Love gnocchi? Then get to know gnudi, a delicate Italian dumpling similar to gnocchi but based on ricotta cheese, not potato. This recipe adds Swiss chard to the dough and serves the dumplings over a light and fresh cherry tomato sauce.
Dust a rimmed baking sheet with flour. Bring a large pot of salted water to a boil; add the Swiss chard and cook until wilted, 2 to 3 minutes. Remove the chard with tongs and transfer it to a kitchen towel. (Reserve the pot of water.) Squeeze the chard dry in the towel, then transfer it to a food processor and process until finely chopped.
Combine the chard, ricotta, Parmesan, whole egg and egg yolks, grated lemon zest and 1/2 teaspoon each salt and pepper in a large bowl; mix well. Mix in the flour until just combined. Scoop tablespoonfuls of the mixture onto the prepared baking sheet, then gently shake the pan to coat the gnudi in flour. Freeze at least 10 minutes.
Meanwhile, combine the olive oil and garlic in a large skillet over medium heat and cook until the garlic is golden, about 3 minutes. Remove the garlic with a slotted spoon and reserve. Increase the heat to high; add the tomatoes and cook, stirring, until they begin to pop. Reduce the heat to medium; stir in the tomato paste and red pepper flakes. Add 1 1/2 cups water, the lemon zest strips and reserved garlic. Cook, crushing the tomatoes, until thickened, 8 to 10 minutes; stir in the lemon juice. Remove the strips of lemon zest. Divide the sauce among bowls.
Return the pot of water to a low boil. Working in two batches, gently add the gnudi and cook until they float, then cook 1 minute longer for a total of about 4 to 5 minutes. Remove with a slotted spoon and add to the bowls. Drizzle with olive oil and top with Parmesan.