Preheat the oven to 450 degrees F (230 degrees C). Line a baking sheet with aluminum foil; lightly grease with oil.

Combine bread crumbs and milk in a small bowl; soak until bread crumbs absorb milk, about 30 minutes.

Combine bread crumb mixture, lamb, egg, garlic, 2 tablespoons 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; place on the prepared baking sheet.

Cook in the preheated oven until slightly browned, about 15 minutes. Remove from oven; set aside.

Combine meatballs, tomato sauce, chicken stock, mint, and pepper flakes in a large saucepan over medium heat until meatballs are no longer pink inside, about 45 minutes.