Place pumpkin, tomatoes, capsicum and garlic in a roasting pan. Drizzle over 2 tablespoons of the oil and toss to coat the vegetables. Sprinkle over the cardamom, cayenne, coriander and turmeric. Bake in the oven for 20 minutes.
Meanwhile, heat the remaining oil in a deep frypan over medium heat. Add the mustard and cumin seeds and cook for 1 minute until the mustard seeds start to pop. Add the onion and ginger, stir to combine and cook for 3 minutes. Add the curry leaves, stock and half the coconut milk. Increase the heat to a simmer.
Squish the roasted garlic out of the skins into the coconut mixture. Stir in the tomato paste and remaining coconut milk. Add the tofu and roasted vegetables, stirring gently. Season to taste. Simmer 5 more minutes.