In a large skillet, heat the olive oil over medium heat.
Add the chopped onion and cook until softened and golden brown, about 5 minutes.
Stir in the minced garlic and cook for another minute.
Add the ground beef or lamb to the skillet and cook until browned. Break up the meat with a spoon as it cooks.
Stir in the tomato paste, ground cumin, ground coriander, ground cinnamon, ground allspice, salt, and black pepper. Cook for 2 minutes to let the flavors combine.
Add the rinsed rice, fresh parsley, and fresh mint to the skillet. Mix well to combine all ingredients.
Remove from heat and let the filling cool slightly.
Carefully stuff the hollowed zucchini with the rice and meat mixture. Pack the filling gently to ensure it’s well-stuffed.
Arrange the stuffed zucchini in a large pot or Dutch oven.
Pour the chicken or vegetable broth over the stuffed zucchini. If using, add the canned diced tomatoes to the pot for additional flavor.
Bring to a boil, then reduce the heat to low, cover, and simmer for about 45 minutes to 1 hour, or until the zucchini are tender and the rice is fully cooked.
Check the pot occasionally and add more broth or water if needed.
Transfer the stuffed zucchini to a serving platter.
Enjoy your meal!