Ingredients:

250 grams jaggery 
6 teaspoons mustard seeds/rai 
2 teaspoons fenugreek seeds/methi 
15 black peppercorns 
1 small piece cinnamon 
1 teaspoon oil
4 teaspoons chilli powder
2 teaspoons turmeric/haldi powder 
1 cup lime juice

Preparation:

Melt jaggery in a little water into a thick syrup.
Roast rai and methi and grind to a fine powder along with peppercorns and cinnamon.
Heat oil and fry chilli and haldi powders.
Mix all the above with lime juice.
The sauce should be bottled and kept aside to mature for at least a week prior to consuming.