Pat dry the meat on all sides on a sheet tray or platter. Next, season well with salt and pepper. Briefly set to the side. For a deeper Maillard crust, you can also place the seasoned meat on a rack and leave it uncovered in the fridge for up to 24 hours.
Add the pancetta to a large rondeau or Dutch oven pot over low to medium heat and cook for 5 to 7 minutes or until crispy and the fat is rendered. Set the lardons to the side.
Turn the heat high and untouched; sear the beef for 3 to 4 minutes. Flip it over and turn the heat to medium. Cook for 6 to 8 minutes or until well-browned. Once I flip it, is when I prep the onions.
Once browned, set the beef to the side. Add half the julienne onions, season with salt, and sauté over medium heat for 10 minutes. Then, turn the heat low and cook for 20 minutes while occasionally stirring until well-browned.
Mix the carrots and celery and cook over medium heat for 10 minutes.
Stir in the tomato paste and cook for 3 to 4 minutes or pince. The tomato paste should be a rust color.
Add the beef, cooked pancetta, thyme, 10 to 12 torn basil leaves, cherry tomatoes, and white wine back in and cook until there is maybe just ½ cup of liquid left. This takes about 5 to 6 minutes.
Cover everything with the remaining julienne onions and beef stock, season with salt and pepper, and stir to combine.
Place a lid on the pot and cook it over low heat for 3 hours. Stir it every 30 to 45 minutes. Then, remove the lid and cook it for 1 hour. If it looks dry, you may need to add more beef stock.
Break up the beef so that it shreds apart and incorporates into the sauce. Adjust the seasonings with salt and pepper.
Next, boil the pasta in a large pot of salted water for 75% of the recommended cook time.
Strain it and add it to a large saucier pan along with 1 cup of the pasta water, plenty of the Genovese sauce, grated Parmigiano Reggiano, and the remaining basil leaves. Cook over low heat to finish cooking the pasta. The flavor will be better as the sauce flavors marry into the pasta.
