Meatballs
In a large mixing bowl, stir together the Panko, milk, cream, egg, allspice, salt, and pepper. After a few minutes, add the beef, pork, onion, and parsley; mix thoroughly. Using a tablespoon and clean hands moistened with water, roll neat meatballs, setting them aside on a clean tray or platter.
Heat the oil in a large sauté pan over medium heat. Working in two or three batches to prevent overcrowding, fry the meatballs, browning them one side for a few minutes, then turning them over, reducing the heat, and finishing them, covered, until cooked through. Set aside in a clean bowl or tray covered with aluminum foil.
Sauce and Noodles
Bring a stockpot of salted water to a boil.
Meanwhile, to make the sauce, melt the butter in a large sauté pan over medium heat, add the onion, and sauté until tender, 4 to 5 minutes. Whisk in the flour to make a roux and continue whisking for about 2 minutes. Whisk in the stocks and continue whisking a few minutes until smooth. Stir in the milk, sugar, Worcestershire sauce, and mustard, continuing to whisk until the sauce thickens. Stir in the cream and reduce the heat to a simmer.
Cook the noodles in the boiling water until al dente, tender but still slightly chewy, following the manufacturer’s suggested cooking time. Drain, return the noodles to the pot, and stir in the butter.
Divide the noodles among serving plates, spoon the meatballs and sauce alongside, and garnish with chopped parsley.