1. Preheat the oven to 500°F/260°C/gas 10. Arrange the eggplant/aubergine halves, flesh-side down, on a rimmed baking sheet/tray. Roast until very soft and tender when the flesh is pierced with a fork, 15 to 20 minutes. Set aside to cool for 10 minutes. Using a paring knife, peel back the skin and discard. Transfer the cooked flesh to a cutting board and finely chop.

2. In a 10-in (25-cm) frying pan, preferably nonstick, heat the oil over medium heat and swirl to coat the pan. Add the onion and sauté until soft but not brown, 5 to 7 minutes. Add the garlic and ginger and sauté until fragrant, about 1 minute. Add the tomatoes and tomato paste/tomato purée. Sauté, stirring frequently, until the tomatoes soften, about 3 minutes. Add the chili powder, salt, cumin, coriander, and turmeric. Sauté to incorporate the spices, 1 minute longer. Add the roasted eggplant/aubergine and sauté, stirring constantly, until the mixture is well combined, about 2 minutes. Adjust the heat to medium-low and gently stir in 1 tbsp of the cilantro/fresh coriander and the water and yogurt. Cook over low heat until slightly thickened and a good dipping consistency, about 5 minutes. Transfer to a serving bowl, garnish with the remaining 1 tbsp cilantro/fresh coriander, and serve immediately.