Heat vegetable oil in a skillet over medium heat; add cumin seeds, bay leaves, and red chilli. Cook until cumin seeds begin to sputter, 1 to 2 minutes, stirring constantly.
Cook and stir tomatoes and ginger piece into cumin mixture until all the water cooks out of tomatoes, about 5 minutes. Stir jaggery and dates into tomato mixture; cook until jaggery dissolves and the mixture thickens, about 5 more minutes. Add black salt. Remove ginger piece and bay leaves from chutney before serving.