In a large bowl, combine ground turkey, bread crumbs, egg, garlic, parsley, allspice, nutmeg, onion powder, salt and pepper. Add bread crumbs if mixture is too wet.
Shape mixture into 1-inch balls and arrange on a baking sheet.
Bake for 15-20 minutes, until cooked through (165 degrees). Meanwhile, make the gravy.
In a large skillet over medium heat, melt the butter. Add the flour and cook for about 2 minutes, stirring continuously, until it begins to turn golden.
Slowly whisk in the chicken broth. Then add the Worcestershire sauce, soy sauce and dijon mustard.
Let simmer for about 5 minutes, until thickened slightly. Reduce heat to low and stir in sour cream. Season with salt and pepper, to taste.
Once the meatballs are done baking, add them to the skillet with the sauce and continue to cook for a couple minutes, spooning the sauce over the meatballs.
Garnish with parsley and plate over mashed potatoes, rice, or egg noodles.