Make sweet and sour tomato launji using grandmother's old recipe.

500 grams red tomatoes

1/2 cup jaggery

2 teaspoons fennel

1/2 teaspoon cumin

1/2 teaspoon nigella seeds

a pinch of asafoetida

1/2 teaspoon red chili powder

1/2 teaspoon turmeric powder

Oil

salt as per taste