01 -
Heat a skillet over medium heat. Add the fenugreek, fennel, and nigella seeds to the skillet and toast until very fragrant, about 3-5 minutes. Remove to a bowl and let cool. Add the asafetida and powder everything together in a spice grinder or blender.
02 -
Place the lime pieces in a clean, dry glass or ceramic bowl. Add the ground spice mixture along with the cayenne (or paprika), turmeric, and salt. Mix well with a clean, dry spoon to ensure all lime pieces are coated.
03 -
Heat the oil in the same skillet you used to toast the spices. Once it's hot, add the mustard seeds. Wait until they begin to sputter and pop, then turn off the heat immediately.
04 -
Carefully, standing back a little to avoid splatters, pour the hot oil with mustard seeds into the bowl with the limes and spices. Mix thoroughly, then transfer the entire mixture to a sterilized quart-sized mason jar.
05 -
Place the mason jar in direct, hot sunlight on your deck, porch, or windowsill for 5-7 days, for at least 6-8 hours each day. Turn the mason jar upside down and around daily to ensure the sauce and spices move around and all lime pieces get equal exposure.
06 -
Once the pickle has fermented to your liking (the limes will soften and the flavors will meld), refrigerate immediately. The pickle will continue to develop flavor over time and can last for months when properly stored.