Serves 4 to 6 INGREDIENTS 3 tablespoons canola oil 1 teaspoon cumin seeds ¼ teaspoon black peppercorns 4 whole cloves 4 green cardamom pods 3 whole dried red chiles 1½-inch piece of fresh ginger, minced 4 fresh or 6 frozen curry leaves, torn into pieces (optional) 2 red onions, finely chopped 3 fresh hot green…