(optional but very helpful for flavor)
Prepare the limes - Cut each lime into 8 pieces
Place the cut limes into a small fermenting vessel (I used a ½ gallon glass wide-mouth jar) and toss with the salt, turmeric and vinegar. I now prefer using a ½ gallon Mason Jar with an airlock such as this.
Cover with a lid (not screwed on as you need to allow gas pressure to escape), a towel, or better yet an airlock. Let it ferment for 4 weeks, stirring every few days. This initial fermentation period helps to tenderize the lime peel and to make them more edible.
After letting the limes ferment for 4 weeks, begin the next stage by toasting the mustard seeds in a pan. Toasting the seeds helps to moderate their heat and enhances the flavor.
Once the seeds have cooled add the mustard seeds, oil, asafoetida powder, fenugreek (methi powder) and cayenne pepper.
Allow to sit for 2+ weeks. This resting period will allow the fermentation to continue and also for the flavors to merge and settle in.
Jar it up and refrigerate - This should keep fairly indefinitely when refrigerated. I've enjoyed the last bit of an old batch recently after about 4 years and it was still as potent and delicious. Always be your own best judge when it comes to food safety.
