Combine ground beef, onion soup mix, allspice, crushed potato chips, garlic, oregano, and evaporated milk. Form into meatballs about the diameter of a quarter.
Heat a large, deep, heavy skillet over medium heat. Coat the bottom with olive oil. When oil begins to shimmer, add meatballs and lightly brown; set aside. You may need to do this in batches.
In the same skillet, melt butter. Add sliced mushrooms and sprinkle with salt. Saut� mushrooms until soft and lightly browned. Stir in flour and cook one minute, stirring often. Add beef broth and stir, scraping up browned bits from the bottom of the pan, until smooth. Return meatballs to the skillet and simmer gently about 5 minutes until meatballs are cooked through. Stir in cream and return to a simmer, but do not boil.
Serve potato chip meatballs with mushroom gravy over cooked noodles or rice and garnish with chopped parsley.