Place meatloaf mix in a large mixing bowl; crumble bread over meat and knead with hands to combine. Add milk and egg to meat mixture. Knead onion, nutmeg, cloves, salt, and pepper into meat mixture until well-combined. Form mixture into six equal-sized balls.
Melt butter in a Dutch oven over medium-high heat. Cook and stir meatballs in hot butter until browned on all sides, 5 to 10 minutes. Stir water, tomatoes, beef broth, and onion soup mix into Dutch oven; bring to a boil, reduce heat to medium-low, and simmer until meatballs are tender and cooked through, about 1 hour.
