Wash 1 pound (500 grams) of tomatoes and wipe them with a kitchen towel. Chop the tomatoes into small pieces and keep them aside.
Heat 2 tablespoon vegetable oil in a pan.
Once the oil is hot, add ¼ teaspoon asafoetida, ½ teaspoon cumin seeds, ½ teaspoon mustard seeds, ¼ teaspoon onion seeds, ¼ teaspoon fenugreek seeds, and 2 teaspoon chopped green chili and let them crackle for 4-5 seconds.
Add 1 teaspoon grated ginger, chopped tomatoes, salt to taste, and 1 teaspoon red chili powder to the pan and cook on medium heat for 10-12 minutes. Keep stirring at regular intervals.
Add 3 oz (85 g) crumbled jaggery and cook for another 4-5 minutes until the chutney thickens and becomes dark in color.
Remove the pan from heat and let the chutney cool down completely. Transfer it in a glass jar and refrigerate for up to a week.
Some people make this chutney with sugar but I prefer the taste of jaggery. Jaggery is also a healthy alternative to sugar and adds a unique taste in the chutney which sugar won’t do.Adjust the amount of red chili and green chili as per your taste.You can add ½ cup chopped seedless dates along with tomato and reduce the amount of jaggery a bit. This variation of tomato chutney tastes delicious too.To make Bengali sweet and sour tomato chutney, heat mustard oil in a pan. Add panch phoran and ginger, and fry for a few seconds. Add chopped tomatoes, cover, and cook for 8-10 minutes. Now add salt, sugar, and water and cook for another 2-3 minutes.