1. Prepare the Ingredients: Thinly slice 3 ½ to 5 pounds of yellow onions. Chop the carrots and celery into small cubes. Cut the beef into large chunks if not using pre-cut stew beef. Season the beef generously with salt and pepper.
2. Sear the Beef: Heat olive oil in a large, heavy-bottomed pot over medium-high heat. Add the seasoned beef in batches to avoid overcrowding and sear each piece on all sides until a rich brown crust forms. Remove the seared beef from the pot and set it aside.
3. Sauté the Vegetables: In the same pot, add more olive oil if needed and sauté the chopped carrots and celery until slightly softened, about 3 to 5 minutes. Lower the heat to medium and add the sliced onions, cooking until soft and fragrant while stirring frequently.
4. Deglaze the Pot: Optional- Pour in a splash of white wine to deglaze the pot, scraping up any browned bits from the bottom using a wooden spoon. Allow the wine to evaporate.
5. Combine Ingredients: Return the seared beef to the pot. Add enough water or beef stock to cover the ingredients halfway.
6. Slow Cook the Sauce: Bring the mixture to a gentle simmer, cover the pot, and cook over low heat for approximately 3 hours. Stir occasionally and ensure there’s enough liquid to prevent the sauce from drying out. By the end, the onions should form a creamy, caramelized sauce.
7. Cook the Ziti: In the last 20 minutes of sauce cooking time, prepare the ziti pasta according to the package instructions. Drain and set aside.
8. Serve: Plate the cooked ziti pasta and top with generous amounts of the sauce. Serve the beef pieces whole or shred them to incorporate into the sauce.
9. Garnish: Sprinkle grated Pecorino cheese over the dish before serving. Enjoy your Ziti alla Genovese with family or friends.