For the Fresh Pasta Dough:

• 3½ cups (420 g) Type “00” flour or high-quality unbleached all-purpose flour for best results
• 5 large eggs

For the Swiss Chard, Ricotta, and Prosciutto Filling:

• 1 lb Swiss chard stems removed and leaves roughly chopped
• 1½ tablespoons (22 g) unsalted butter
• ¼ cup finely chopped shallot approximately 1 medium shallot
• 3 tablespoons finely chopped prosciutto about 2 to 3 thin slices
• 1 large egg yolk
• 1 cup whole-fat ricotta cheese drained if excessively wet
• ¼ cup grated Parmigiano-Reggiano cheese
• ¼ teaspoon freshly grated nutmeg
• freshly ground black pepper to taste
• kosher salt to taste

For Assembly:

• semolina flour for dusting surfaces and trays
• 1 large egg, beaten for brushing pasta edges (egg wash)

• Prepare the Homemade Pasta Dough: Begin by mounding the flour directly onto a clean countertop or a large wooden cutting board. Using your fingertips, create a generous well in the center of the flour, deep enough to see the countertop. Carefully crack all five eggs into this well. Using a fork, gently start incorporating the flour from the inner edges of the well into the egg mixture. Whisk continuously until the liquid eggs are fully absorbed and no longer runny.
• Next, using floured hands or a sturdy bench scraper, continue to work the remaining flour into the egg mixture until a cohesive dough forms. You should be able to squeeze the dough firmly without it sticking excessively to your hands. Now, knead the pasta dough diligently for 10 minutes. The dough should become remarkably smooth, elastic, and springy to the touch, indicating proper gluten development.
• Divide the freshly kneaded dough in half. Gently flatten each portion into a disk using the palm of your hand. Wrap each disk tightly in plastic wrap to prevent it from drying out. Allow the dough to rest at room temperature for a minimum of 30 to 45 minutes. This resting period is crucial as it allows the gluten to relax, making the dough much easier to roll later.
• Prepare the Swiss Chard, Ricotta, and Prosciutto Filling: Thoroughly rinse the torn Swiss chard leaves in a colander under cold running water until all grit and dirt are removed. Do not dry the leaves yet. Bring a large pot of generously salted water to a rolling boil. Add the rinsed Swiss chard leaves and blanch for 3 to 4 minutes, or until the leaves are tender and vibrant green. Drain the chard very well and let it cool completely until it’s comfortable enough to handle. Transfer the cooled Swiss chard to a clean kitchen towel or several layers of thick paper towels. Tightly wring out and discard any excess liquid; this step is critical to prevent a watery filling. Finally, finely chop the squeezed Swiss chard and set it aside.
• In a medium saucepan, melt the unsalted butter over medium heat. Add the finely chopped shallots and sauté gently until they are soft and translucent, which should take approximately 3 to 4 minutes. Stir in the finely chopped prosciutto and continue to cook for an additional 2 to 3 minutes, allowing its flavors to meld. Then, add the chopped, blanched Swiss chard to the pan. Sauté the entire green mixture for another 3 to 4 minutes, ensuring any remaining moisture evaporates, before removing it from the heat. Allow this mixture to cool until it is lukewarm.
• In a separate mixing bowl, combine the whole-fat ricotta cheese, the egg yolk, the cooled (lukewarm) Swiss chard and prosciutto mixture, freshly grated nutmeg, and grated Parmigiano-Reggiano cheese. Mix all ingredients thoroughly until they are well combined and evenly distributed. Season the filling mixture generously to taste with kosher salt and freshly ground black pepper. Transfer this flavorful mixture into a large piping bag fitted with a small, round tip for easy and precise application.
• Assemble the Agnolotti: Once the pasta dough has completed its resting period, briefly knead each disk again. If the dough feels a bit sticky after resting (as flour tends to absorb moisture), add a very small amount of additional flour to achieve a non-tacky consistency. Divide each dough ball in half once more, yielding four portions. Take one portion and, using an electric or manual pasta machine, roll the dough disk using the largest-width setting.
• To “laminate” the dough, fold it into an envelope shape: bring one edge into the center, then repeat with the other side, overlapping slightly. Continue to roll the dough through the largest-width setting, always feeding the dough into the machine with the folded seams facing the machine. Repeat this process at least five times. This repeated rolling and folding smooths the dough, strengthens the gluten, and ensures an even, consistent thickness, which is key for delicate stuffed pasta.
• Progressively roll the pasta dough through your pasta machine, reducing the setting with each pass, until you reach setting “5” (or your machine’s equivalent for a very thin sheet). The dough should be almost translucent, allowing light to pass through. Cut the long pasta sheets into manageable 12-inch lengths. Allow the rolled dough sheets to dry slightly at room temperature, either by hanging them on a pasta rack or laying them on a lightly floured surface, until they are no longer tacky but still pliable. To prevent the pasta from becoming too dry and brittle, avoid rolling out too many sheets at once before you begin assembly.
• Take one pasta sheet at a time and lay it flat on a lightly dusted countertop (using semolina flour). Using the piping bag, pipe a thin, straight line of the ricotta filling (about ½-inch in diameter) horizontally along the center of the pasta sheet. Lightly brush the dough adjacent to the filling, on both sides, with the beaten egg wash. Carefully fold one side of the dough over the filling, gently pressing the dough around the filling to eliminate any air bubbles and pressing firmly along the edges to seal. Using a fluted wheel pastry cutter, trim the filled pasta strip away from the rest of the sheet, leaving a ½ to ¾-inch edge around the filling. Discard the trimmings or save them to cook separately.
  
• With your fingertips, gently indent the dough into equal-sized sections (approximately 1-inch wide) along the length of the filled strip. This creates firm seals between each future agnolotti. Now, with your hands, gently roll the filled dough strip over to the edge, further sealing and shaping the agnolotti. Using your pastry cutter, quickly cut between each indent/seal to form individual agnolotti pieces. Perform this step swiftly to ensure a strong, tight seal, which prevents the filling from escaping during cooking. Place the freshly assembled agnolotti on a large baking sheet generously dusted with semolina flour to prevent sticking.
• Repeat the assembly process with the remaining pasta sheets and filling until all your agnolotti are prepared. These delicate parcels can be stored in the refrigerator overnight, cooked immediately for instant gratification, or frozen. To freeze, arrange them in a single layer on the semolina-dusted sheet tray until solid, then transfer them to a freezer-safe ziploc bag for long-term storage.
• To cook your homemade agnolotti, bring a large pot of heavily salted water to a rolling boil. Carefully add the agnolotti and cook until they float to the surface and are perfectly al-dente. Fresh agnolotti cooks very quickly, typically in just 2-4 minutes. Frozen agnolotti will take a few minutes longer.