1-Cut the vegetables into fine pieces. Add salt and red chilli powder and mix.
2-In two tsps of oils add mustard seeds.
3-when it pops add the fenugreek powder and asafoetida.
4-Add this to the vegetable mix. Heat the remaining oil in the same pan and add it to the vegetables.
5-For the next two days stir and shake well once a day.
6-The same method can be followed for sour apple, guava unripe) or any vegetable which has a sour taste.