How to Make It
In a small bowl, cover the currants with the vinegar and let stand until plumped, about 10 minutes.
Meanwhile, in a medium saucepan, heat the oil until shimmering. Add the shallots, garlic and ginger and cook over moderate heat, stirring occasionally, until softened and just starting to brown, about 5 minutes. Add the tomato paste and cook, stirring, until the vegetables are evenly coated, about 1 minute. Add the tomato puree, diced tomatoes, sugar, currants and vinegar and bring to a boil over high heat. Simmer over moderate heat, stirring frequently, until thickened, about 20 minutes. Stir in the chopped curry leaves and crumbled fenugreek leaves and let cool. Season the tomato jam with salt and pepper.
Fresh curry leaves and dried fenugreek leaves are available at Indian markets and on amazon.com.