Arrange the lemon pieces in a single layer in a steamer. Steam over medium heat until they are tender.

Heat the oil in a pan and add the curry leaves, mustard seeds, and fenugreek seeds. Once they begin to crackle, add the ginger, garlic, green chiles, turmeric, salt, and ground red chile.

Stir-fry the aromatics for a couple of minutes to release their flavors, then fold in the steamed lemons.

Continue to stir-fry briefly to combine, then remove from heat and cool before transferring to a clean jar.