It took a little while but here's the Tamatar Kasaundi recipe. It's totally delicious. As you can see from the number of chillies in the recipe it is quite spicy ... so a little goes a long way.
Tamatar Kasoundi (Tomato Oil Pickle)
1 1/2 tablespoons black mustard seeds
1 1/2 cups malt vinegar
3/4 cup chopped fresh ginger
20 cloves garlic
20 fresh green chillies
2 kg (4 lb) firm ripe tomatoes
1 1/4 cups vegetable oil
1/1/2 tablespoons ground turmeric
4 tablespoons ground cummin
1-2 tablespoons chilli powder, to taste
1 cup sugar
1 tablespoon salt
Soak mustard seeds in vinegar overnight and grind in electric blender.
Peel ginger and garlic, chop roughly and add to mustard and vinegar. Blend on high speed until pureed.
Cut chillies in halves lengthways and remove seeds.
Peel and chop the tomatoes.
Heat oil in large, heavy saucepan until smoking hot. Allow to cool slightly, then add the ground turmeric, cummin and chilli powder and fry, stirring for a few minutes.
Add the tomatoes, chillies, blended vinegar mixture, sugar and salt. Simmer until tomatoes are reduced to a pulp and the oil starts to float on top.
Taste and add more salt if required.
Bottle and seal when cold.
Leave pickle to mature for a week before using.
Recipe from "The Complete Asian Cookbook" by Charmaine Solomon