Chop the onion, garlic, carrots, and pepper finely.
Heat the oil in a large pan (Dutch oven or another large heavy-bottomed pan). Cook the vegetables with a pinch of salt for about 10 minutes until they are soft.
Add sugar and tomato paste, stir well for 1 minute and let caramelize slightly.
Pour the wine, let bubble away for 1 or 2 minutes.
Add the chopped tomatoes, stock, bay leaves, rosemary, red chili flakes, or cayenne pepper. Stir well and simmer gently for about 20 minutes.
Add the shredded or chopped meat, stir well. Simmer for about 10-15 minutes more until the meat is heated through and it had time to absorb the flavors.
Adjust the taste with Worcestershire sauce, salt, and pepper. Sprinkle with some chopped parsley if desired.
While the ragu sauce cooks, cook the pasta in plenty of salted water. Drain and serve with the sauce immediately.