Preheat the oven to 200°C (390°F) using conventional oven settings (top and bottom heat). Wash the eggplant and cut it into 1 to 2 cm (½ to ¾ inch) cubes. Halve the onion and cut it into strips about 0.5 to 1 cm (¼ to ½ inch) thick. Place the lentils in a sieve and rinse thoroughly under cold running water; set aside.

Combine garam masala, paprika, cumin, chili powder, turmeric, olive oil, and water in a small bowl. Place the eggplant and onions in an ovenproof skillet (or casserole dish) and toss with the spice mixture. Season the vegetables generously with salt and pepper, then bake at 200°C (390°F) for 20 minutes, or until the vegetables are tender and have developed some roasted aromas.

After 20 minutes, remove the pan from the oven. Add the lentils and pour in the coconut milk and tomatoes. Stir well to loosen any browned bits from the bottom of the pan, then cover the pan and return it to the oven for another 25 to 35 minutes, or until the lentils are tender.

Remove the eggplant curry from the oven and season with salt, pepper, and a little fresh lemon juice. Stir in the coriander and serve the curry with yogurt and your choice of side dishes.