Line a baking sheet with aluminum foil; oil lightly.
Combine bread crumbs and milk in a small bowl. Soak bread crumbs until milk is absorbed, about 30 minutes.
Combine bread crumb mixture, lamb, egg, garlic, olive oil, tomato paste, rosemary, cumin, salt, oregano, black pepper, cinnamon, and cayenne pepper in a large bowl.
Form lamb mixture into 2-inch meatballs and place on the prepared baking sheet.
Cook meatballs in the preheated oven until they are slightly browned, about 15 minutes. Remove from the oven and set aside.
Combine meatballs, tomato sauce, chicken stock, fresh mint, and red pepper flakes in a large sauce pan over medium heat until meatballs are no longer pink inside, about 45 minutes.
