In a large mixing bowl, combine ground beef, breadcrumbs, Parmesan cheese, milk, eggs, onion, garlic, salt, pepper, allspice, and nutmeg. Mix gently until just combined. Avoid overmixing to keep the meatballs tender.
2 lbs ground beef, 1/2 cup breadcrumbs, 1/4 cup grated Parmesan cheese, 1/4 cup 2% milk, 2 large eggs, 1/2 medium onion, 1/2 cluster garlic, 1 tsp salt, 1/2 tsp black pepper, 1 tsp allspice, 1/2 tsp nutmeg