Special equipment: an immersion blender
Preheat the oven to 425 degrees F. Line a baking sheet with parchment.
For the sauce: Combine the tomatoes, onions, garlic and bay leaf in large Dutch oven. Season with salt and pepper and bring to a simmer over medium heat. Simmer, partially covered, until the tomatoes have broken down and the sauce has slightly thickened, 30 to 45 minutes. (If needed, cook uncovered for another 10 minutes until thickened to desired consistency.) Remove the bay leaf and pulse the sauce with an immersion blender until slightly smooth but still rough. Add the butter and half of the parsley and season to taste. Keep warm over medium heat until the meatballs are ready.
For the meatballs: While the sauce is simmering, start on the meatballs. In a large saute pan, heat the olive oil over medium-high heat. Add the onions and saute until tender, 5 to 7 minutes. Remove the pan from the heat.
Combine the Italian seasoning, red pepper flakes, sage and 1/2 cup of the milk in a small bowl and set aside to allow the dried herbs to reconstitute, about 5 minutes. This will soften the spices and release their flavors.
Transfer the sauteed onions and milk mixture to a large bowl. Add the ground beef, couscous, grated Parmesan, ricotta, eggs, garlic and 2 teaspoons kosher salt. Combine with your hands, making sure not to overmix. If the mixture looks too dry, add the remaining 1/4 cup milk. Using a 1 1/2-ounce-portion scoop or a scant 1/4 cup, scoop the mixture onto the prepared baking sheet. The mixture should yield 30 meatballs.
Bake the meatballs until firm on the outside but slightly undercooked in the center, 10 to 15 minutes. Add the meatballs to the blended sauce and cook until cooked through, 10 minutes.
For the pasta: In a large high-sided saute pan, bring 5 cups water, 3 cups of wine, and some salt to a boil. Add the pasta and cook until al dente, about 9 minutes, pressing the pasta down as it cooks to make sure it is fully submerged in the liquid.
Strain the cooked pasta and return it to the pan along with any remaining wine (there should only be a little bit, less than 1/4 cup) and 1 cup of the sauce. Toss to combine. Serve immediately, topped with more sauce and the meatballs. Garnish with the remaining parsley and shaved Parmesan.