Like most lasagna dishes, this one can be a bit tricky, especially if you've never made one before. But if you follow the recipe step by step you should be able to come out with one of the best lasagnas you've ever tasted.
Divide the pasta dough into 3 portions. Roll each one out through the thinnest setting on a pasta machine and lay the sheets on a lightly floured work surface to dry for 10 minutes. cut the pasta into 10" x 5" strips and cover with a damp kitchen towel.
Bring 6 quarts of water to a boil in a large pot, and add 2 tablespoons salt. Set up an ice bath next to the stovetop, and add the oil. Cook the noodles, 6 to 7 at a time, in the boiling water until tender, about 1 minute. Transfer to the ice bath to cool, then lay out on clean kitchen towels to drain.
Preheat the oven to 350°F.
Assemble the lasagna in a 10" x 20" lasagna pan (or use two 9" x 12" pans): spread 1/2 cup ragu over the bottom of the dish, then top with a layer of pasta, a layer of ricotta, a layer of polpette and sausage, and a layer of Parmigiano and mozzarella.
Continue until you have at least 3 layers, finishing with cheese.
Bake for 1 hour and 15 minutes, or until the edges are bubbling. Let rest for 15 minutes before serving.
To make the pasta:
Mound the flour in the center of a large wooden board. Make a well in the center of the flour and add the eggs. Using a fork, beat the eggs together and then begin to incorporate the flour, starting with the inner rim of the well.
As you expand the well, keep pushing the flour up to retain the well shape (don't worry if it looks messy). When half of the flour is incorporated, the dough will begin to come together. Start kneading the dough, using primarily the palms of your hands.
Once the dough is a cohesive mass, set the dough aside and scrape up and discard any dried bits of dough.
Lightly flour the board and continue kneading for 10 minutes, dusting the board with additional flour as necessary. The dough should be elastic and a little sticky. Wrap the dough in plastic wrap and allow to rest for 30 minutes at room temperature before using.
To make the ragu:
In a large Dutch oven, heat the olive oil over medium heat until smoking. Season the veal and beef with salt and pepper to taste, and sear, in batches to avoid overcrowding the pot, until dark golden brown. Transfer to a plate.
Add the onion to the pot and sauté, scraping the bottom of the pot with a wooden spoon to loosen any brown bits, until golden brown and very soft, about 10 minutes. add the wine, browned meat chunks, tomatoes, sausages and red pepper flakes and bring just to a boil. Reduce the heat to a simmer and cook, stirring occasionally and skimming off the fat as necessary, for 2 1/2 to 3 hours.
Remove from the heat, remove the meat and sausages, and set aside. Adjust the seasoning with salt and pepper.
To make the polpette (meatballs):
In a shallow bowl, soak the bread cubes in water to cover for 20 minutes. drain the bread cubes and squeeze out the excess moisture.
In a large bowl, combine the bread, beef, eggs, garlic, pecorino, parsley, pine nuts, salt and pepper and mix with your hands just until blended. With wet hands, form the mixture into 12 to 15 large meatballs.
In a heavy-bottomed skillet, heat the olive oil over high heat until almost smoking. Add the meatballs, working in batches if necessary to avoid overcrowding the pan, and cook, turning occasionally, until deep golden brown on all sides, about 10 minutes per batch. Remove from the heat.