Boil 3 cups of water in a deep pan.

Reduce heat to low and add washed whole lemons.

Simmer for 10-15 minutes.

Drain the lemons and let them cool completely.

Cut lemons into quarters (or desired size) and remove seeds.

In a bowl, combine black pepper, rock salt, red chilli powder, and turmeric powder.

Mix well.

Heat mustard oil in a tadka pan until smoking hot.

Add mustard seeds; once they splutter, add kalonji and asafoetida.

Remove the pan from heat and pour the hot oil and spices over the lemon chunks.

Mix thoroughly.

Let it sit for at least 1 hour, allowing the spices to seep into the lemons.

Serve with parathas, yogurt, rice, poriyal, or Thakkali rasam.