In a small bowl, mix the breadcrumbs and milk. In a large bowl, mix the turkey or veal, egg, onion, 2 tablespoons parsley, Dijon, garlic, nutmeg and allspice; season with salt and pepper. Squeeze the excess milk from the breadcrumbs. Discard the milk; add the breadcrumbs to the large bowl. Mix to combine. Roll into walnut-size balls.
Bring a large pot of water to a boil for the noodles.
In a large, deep skillet, heat the olive oil, two turns of the pan, over medium-high. Add the meatballs; cook until browned, about 3 minutes. Transfer to a plate. Add the butter to the skillet. When it foams, add the mushrooms and cook, stirring occasionally, until browned, about 5 minutes. Add the shallots and stir until softened and slightly browned, 1-2 minutes. Season. Add the tomato paste and stir for 1 minute. Add 2 cups stock and bring to a simmer. Slide the meatballs back into the skillet and simmer until cooked through, 3-4 minutes.
Salt the pasta water. Add the noodles and cook until al dente. Drain the pasta and transfer to a large bowl. Stir the sour cream into the skillet. Mix a few spoonfuls of the sauce into the noodles. Top noodles with meatballs and remaining sauce. Garnish with parsley and dill.