• Start with two onions. Cut off the root and stem ends. Peel the onions and slice them thinly. (Use a food processor if you have one. You'll need to first quarter the onions and make sure each section is small enough to fit into the feeder of the machine. Use the slicing blade on the food processor. Feed the onion sections into the machine while pressing the pulse button until they're sliced.) Set aside the slices from the two onions in a small bowl. Then continue thinly slicing the rest of the onions, placing them in a large mixing bowl.
• Rinse the celery and scrape off any dirt. Pat it dry with a paper towel. Use a knife to trim off each end a bit, then chop the celery into small pieces. Set it aside.
• Pat the beef and pork dry with paper towels. Do not leave any moisture. Cut off any hanging fat from the beef.
• In a tall, 8-quart pot, heat two tablespoons of olive oil on medium-high heat until it's sizzling. Add the meat to the pot and season it with ⅛ teaspoon of salt. Sear the meat on each side to brown it. (Let the meat cook on the first side until it's easy to nudge and flip over. It could take 15 minutes. Use tongs to flip the meat, then brown the second side.) When you can nudge the meat easily, remove it to a platter.
• Add ½ cup of white wine to the pot. Use a wooden spoon to deglaze the pot, scraping up the browned bits until they're not stuck. Add the two onions you sliced at the beginning, plus the chopped celery. Season with ⅛ teaspoon of salt. Brown the onions and celery for up to six minutes, stirring occasionally.
• Add the meat on top of the onions and celery. Transfer the remaining sliced onions to the pot. Add ¼ teaspoon of salt, ¼ teaspoon of black pepper and the bay leaf. Pour 2 ½ cups of hot water over the onions. Stir with a wooden spoon to moisten the onions.
• When the pot starts boiling, lower the heat to a simmer. Loosely cover the pot, with a wooden spoon resting on the edges to prop the lid open. Simmer the sauce for four hours, stirring occasionally to prevent sticking.
• After four hours of cooking, cut up three peeled tomatoes (it's fine to include a little of their juice) and add them to the Genovese sauce. Stir to combine. Loosely cover the pot again and simmer the sauce for another hour, stirring occasionally.
• When the sauce has about 20 minutes left to cook, get the pasta pot ready and cook the pasta according to the directions below.
• After the Genovese sauce has cooked for the 5th hour, turn off the heat. Stir in ¼ teaspoon of red pepper flakes and ¼ teaspoon of salt. Add 3 tablespoons of grated Pecorino and four chopped basil leaves. Stir to combine.

Cook the Pasta

• Fill a large pasta pot ⅔ full with hot water. Add a couple of teaspoons of salt. Cover and heat on high.
• When the water is boiling, add the pasta to the pot and stir briefly. Cook the pasta according to the al dente directions on the package, stirring occasionally so it doesn't stick. Taste the pasta three minutes earlier than it says, to see if it's ready. When the pasta is al dente, drain it in a colander in the sink.
• Add three tablespoons of salted butter to the empty pasta pot to let the butter start melting. Transfer the drained pasta back to the pot. Stir to mix the pasta and butter.

To Serve

• Stir two or three ladles of the Genovese sauce into the pot of cooked pasta. Then, ladle some pasta into each dish and top with more of the pork, beef and onion sauce. Serve with grated Pecorino on top.
• Store leftover sauce and pasta separately, covered in the refrigerator for up to four days. You can freeze the Genovese sauce in sealed containers and use it within three months, for the best quality.