In a large nonstick skillet, heat olive oil over medium heat and add onions and garlic. Sauté until onions are translucent, about 4-5 minutes.
Add celery and parsley and cook until soft, about 3-4 more minutes. Set aside to cool.
In a large bowl, combine beef, turkey, egg, onion mixture, breadcrumbs, ¼ teaspoon salt, pepper and allspice. Mix well and form into 16 meatballs.
Add beef broth to the pan and bring to a boil. Reduce the heat to medium-low and slowly drop meatballs into the broth. Cover and cook about 20 minutes, until cooked through.
Remove the meatballs with a slotted spoon and set aside in a serving dish.
Strain the broth, transfer to a blender with cream cheese and blend until smooth.
Return to the skillet with the meatballs and simmer.
