In a medium Dutch oven, heat the oil over medium- high heat and cook the pancetta until it is crisp and the fat is rendered, 6 to 8 minutes. Add the onion, carrot, celery, pepper, and 1 teaspoon of the salt and cook until the vegetables are lightly caramelized, stirring occasionally, 4 to 6 minutes. Increase the heat and stir in the sirloin and veal. Cook, stirring and breaking the meat into small pieces, until the meat is well browned, about 5 minutes. Add the tomato paste and cook, stirring, for 2 minutes. Stir in the wine and garlic and cook until the wine is nearly evaporated, about 2 minutes. Add the stock and reduce the heat to low. Cook, partially covered, until the liquid is almost completely evaporated, about 10 minutes.
Add 1 ⁄2 cup of the half-and-half and continue cooking for 30 to 40 minutes, adding the remaining half- and- half little by little as the sauce reduces. The sauce should be very thick and rich. Season with the remaining 1⁄2 teaspoon salt and additional black pepper to taste; you may not need any more seasoning, depending on the stock that you used. Stir in the parsley.
Serve the sauce tossed with cooked pasta and garnish with grated cheese.
