Add the pancetta to a large saucepan and place over medium heat. Allow the pancetta to render its fat and crisp up then remove the pancetta from the pan and set aside.
Pour the oil into the pot along with the onion, carrot, and celery and season with salt and pepper. Cook the vegetables down until softened and lightly golden brown, about 5 minutes. Add in the garlic, fennel seeds, Italian seasoning, and crushed red pepper flakes and cook for 30 seconds to toast the spices and cook off the raw garlic.
Add the ground beef and sausages to the pot and, using a wooden spoon or spatula, break the meat up into a fine crumb. Cook, stirring occasionally, until lightly golden and almost cooked through, about 6 to 8 minutes. Stir in the tomato paste then deglaze the saucepan with the red wine, scraping the bottom of the pan to release any stuck-on bits.
Carefully pour in the crushed tomatoes, season with sugar, and turn the heat down to low. Using a sharp knife, remove the rind from the wedge of Parmigiano Reggiano and add it to the pot along with the cooked pancetta. Place an off-kilter lid over the pot to help avoid splatter and simmer the sauce for at least 15 minutes or for up to 1 hour, adding a splash of water or wine if the sauce cooks down too much.
Meanwhile, bring a large pot of water to a boil and season well with salt. Cook the pasta according to the package directions. Reserve about 1 cup of the pasta cooking liquid before draining the rest and returning the pasta to the pot.
Spoon over as much of the Bolognese as you’d like, adding a splash of the pasta cooking liquid to bring everything together. Grate in some Parmigiano Reggiano, toss to combine, and serve with more grated cheese on top.
Store the remaining sauce in resealable containers in the fridge for up to 3 days or in the freezer for up to 3 months.
