1. Heat olive oil in a large saucepan over medium heat. Add the lamb shank and sear it for a couple of minutes on each side, until lightly browned. Add onion and stir until translucent, about 5 minutes. Add  garlic and sauté for another 2 minutes. 
2. Stir in tomato purée and water; season with salt and black pepper. Bring lamb mixture to a boil and reduce heat to low. Simmer lamb in sauce until very tender, at least 1 hour, adding more water as needed. Stir occasionally.
3. Preheat oven to 350 degrees F (175 degrees C).
4. Transfer the lamb shank and sauce to a 2-quart Tagine and stir the okra, diced green pepper and half of the chopped cilantro into the tomato sauce, adding more water if necessary. Adjust salt and pepper; cover with foil.
5. Bake in the preheated oven until okra is tender, about 45 minutes; uncover for last 10 minutes of baking. Sprinkle the top with remaining chopped cilantro and serve with white rice or toasted pita bread.

Enjoy! 👩🏻‍🍳👌🏻