Spray a 6-quart slow cooker with non-stick cooking spray.
Place the diced onion in the bottom of the slow cooker and top with the garlic. Place the pork shoulder on top of the onion and garlic. Pour one can of the crushed tomatoes over the pork and around the sides. Sprinkle the Italian seasoning all over and season with salt and pepper, to taste. Pour the second can of crushed tomatoes over. Cover and cook on low for 11 hours.
Remove the bone and the layer of fat on the pork and discard. Stir in the heavy cream and then stir in the gnocchi. Cover and cook for an additional 1 hour on low. Serve with grated Parmesan or Romano cheese.
Note: Dried gnocchi are found in the pasta aisle at the supermarket (I bought the DeLallo brand). Do not use fresh or refrigerated gnocchi, or they will become too soft during cooking.Nutritional values are based on one serving