Preheat the oven: Preheat your oven to 165°C.
Cook the bacon and pork: Heat a cast-iron pot with the butter and fry the bacon until crispy. Remove the bacon and set it aside. Add the pork shoulder to the pot, season with salt and black pepper, and fry until browned on both sides.
Prepare the sauce: Turn off the heat and add the garlic, chopped onion, celery, carrots, sage, tomato paste, canned tomatoes, red wine, and beef stock to the pot. Stir to combine.
Slow cook the pork: Cover the pot and bake in the oven for 2-3 hours, or until the pork shoulder is tender and easily shredded.
Serve: Shred the pork and mix it into the sauce. Serve the ragu over cooked tagliatelle pasta, topped with fresh mozzarella, Parmesan shavings, fresh herbs, and crushed black pepper.