Step 1In a small bowl, mix together the turmeric, red pepper, coriander, garam masala, cumin and salt to taste.
Step 2Wash the okra and pat it dry. Trim the tops and the ends of the okra and make a lengthwise slit in each piece for stuffing the dry spices. Be careful not to make very deep slits as they will split the vegetable in two. Using a small spoon, stuff the turmeric mixture into each slit okra and set it aside. Save the leftover spice mix.
Step 3Heat the oil in a nonstick skillet over medium heat. Add the cumin seeds and cook until fragrant, about 1 minute. Add the onion, garlic, ginger and kalonji seeds. Cook until the onion is light brown, about 10 minutes.
Step 4Add the tomato, potatoes and okra and stir until the okra and potatoes are well coated with the onion and tomato mixture. Add the leftover spice mix and the fenugreek, reduce the heat, cover and cook until the potatoes and okra are tender, 15 to 20 minutes. Squeeze lemon juice over the stew before serving and garnish it with cilantro.