Slice the tomatoes, smear turmeric and salt on them
and soak them in 1 cup vinegar.Leave for about 2 hours.
Blend together the garlic, ginger, red chillies and 3/4 of the mustard, with a little vinegar.
Heat the oil and add the remaining mustard.
When the mustard crackles, add the fenugreek.
Fry for 2 minutes and then add the blended mixture and fry well for over 20 minutes.
Add the tomatoes and the remaining vinegar.
Stir continuously as the mixture comes to a boil.
When the pickle is almost done, the oil begins to float at the top.
Take it off the heat and let it cool.
Store in a clean bottle.
Will keep for a year.