Combine the pigeon peas and turmeric with 6 cups of water (use 3 cups if not making Osaman) in an Instant Pot or pressure cooker.
Cook at high pressure for 8 minutes. Then allow the pressure to release naturally for at least 10 minutes.
Using a large sieve, strain the dal mixture. Set the liquid aside to make Osaman. Transfer the solids to a medium sized bowl. This is your lachko dal.
Heat a small pan with the ghee added for the vaghaar (also known as tempering or tadka). Once the ghee is hot, add in the mustard seeds, asafoetida dried red chili, curry leaves and sliced green chili. Stir for about 30 seconds or until the curry leaves turn dark green.
Pour three quarters of the spiced ghee over the dal solids, add salt and stir. Garnish with the remaining ghee mixture and serve warm.