Trim the edges of the lemon and cut them into bite-sized pieces. Try to remove the seeds as much as you can and discard them.
Pressure Cooking the pickle with spices-
Add 2 tbsp of oil to the inner pot of the Instant Pot and spread it evenly. Evenly coat the bottom of the inner pot with the oil. Now add the cut lemons.
Next, add all the spices one by one - red chili powder, mustard seed powder, turmeric powder, and salt. Add the 1/2 cup of water on top—no need to mix. Now close the Instant Pot. Make sure the sealing ring is on, and the vent is in the sealing position. Pressure cook for 20 minutes at a high-pressure setting. Let the pressure release naturally. Open the instant pot and mix the pickle now. It will look watery, and it's ok.
Set the IP in saute mode and add the jaggery. Mix it and let it simmer for about 12 to 15 minutes. Partially cover the IP with a lid to avoid the splashing. Mix in between so that the pickle doesn't get stuck in the bottom. The pickle will thicken slowly, and as it cools down, it will thicken more. If you like pickle brine, then simmer it just for 7 to 8 minutes. You can use the pickle brine to make pickle pulav/rice or mix with wheat flour and make spicy pickle brine paratha.
Tempering the pickle
In a separate tempering pan, add the remaining 3 tbsp oil. When the oil is hot, add the mustard seeds, fenugreek seeds, and hing. Let the mustard seeds splutter. Turn off the heat and add it to the pickle.
Mix it well and let it cool before storing in an air-tight container.
I used gingelly oil/sesame oil for this recipe. That's what we regularly use for pickles, but you can use oil of your choice.
As always, adjust the spices according to your taste plus based on the tartness of the lemons.
I did not add any nigella seeds/kalonji in this pickle. But you can add a tsp of kalonji seeds, and it elevates the flavor of the pickle.
I used powdered jaggery for this recipe. You can use grated or shaved ones. If you feel the jaggery may contain impurities, simmer 1/4 cup of water and add the jaggery. Once it dissolves, filter it and add this mixture to the pickle.
Twenty minutes of pressure cooking is sufficient for this lemon variety. But if the skin is thick, you can increase the cooking time to 25 minutes but not more than that.
Pressure Cooker Version
You can add oil to the pressure pan or cooker and add the cut lemon. Then add the spices, turmeric, and salt. Add water and mix it and pressure cook for 4 to 5 whistles. Let the pressure subside and open the cooker. Add the jaggery and simmer it over medium-low heat for about 12 to 15 minutes. Then add the tempering and let it cool.