Preheat the oven to 350°F / 175°C.
Trim, wash, and scrub the vegetables.
Place them in a large baking pan, drizzle with oil, sprinkle with 1 teaspoon (5 ml / 0.2 fl oz) of cumin, and season with salt and pepper.
Toss to coat evenly.
Roast for 30 to 40 minutes, until caramelized and crisp on the outside and soft on the inside.
While the vegetables roast, make the sauce.
Heat 2 tablespoons (30 ml / 1 fl oz) of oil in a large frying pan over medium heat.
Add the curry leaves and let them crackle for a minute.
Add the onion and cook for 10 minutes until soft and golden.
Add the garlic, ginger, and green chiles, and stir-fry for another 3 to 4 minutes.
Add the canned tomatoes with their juice, breaking them up with a spoon. Fill the empty can three-quarters full with water and add it to the pan along with the tomato paste.
Stir to combine.
Simmer for about 15 minutes, stirring occasionally, until the sauce is rich and has reduced.
Stir in the remaining teaspoon of cumin, the garam masala, turmeric, and honey.
Season with salt. If the sauce is too thick, add a splash of water to loosen it.
Add most of the roasted vegetables to the sauce, stirring gently to combine.
Reserve a few for garnish.
Transfer the curry to a serving dish, top with the remaining roasted vegetables, and serve hot with steamed rice or buttered chapatis.
Don't overcrowd the baking pans when roasting the vegetables. Give them plenty of space to ensure they caramelize properly instead of steaming.
Adjust the spice level by adding or removing the seeds from the green chiles. For a milder curry, use just one chile without seeds.
