In a large bowl, combine ground beef (or lamb), breadcrumbs (if using), parsley, cilantro, cumin, coriander, cinnamon, paprika, turmeric, cayenne, salt, and pepper. Mix until well combined. Roll the mixture into small meatballs, about 1 inch in diameter.

Heat olive oil in a large, deep skillet or tagine over medium heat. Add the meatballs and cook for 5-7 minutes, turning occasionally, until browned on all sides. Remove the meatballs from the skillet and set aside.

In the same skillet, add chopped onion and minced garlic. Sauté for 3-4 minutes, until softened. Add crushed tomatoes, chicken broth, honey (if using), lemon zest (if using), olives, lemon juice, ground cinnamon, and ground cumin. Stir to combine.

Return the meatballs to the skillet. Cover and simmer for 25-30 minutes, or until the meatballs are cooked through and the sauce has thickened.

Serve the Moroccan meatball tagine hot, garnished with additional fresh parsley or cilantro if desired. Pair with couscous, rice, or flatbread for a complete meal.