
Nepal
Thakali Khana
A Nepali set meal: rice in the middle, dal, chicken curry, aloo tama and pickle
Whole, unhulled black gram beans, small and black with a pale interior; long cooking turns them creamy and slightly silky.
Urad dal is black gram (Vigna mungo), a small legume that despite its name is not a lentil; whole and unhulled it is black, with a creamy white interior. It tastes earthy and robust and releases starch and mucilage as it cooks, thickening the dish into something velvety, which is exactly what is wanted in Nepal and northern India. It should be soaked overnight and then needs anywhere from one to several hours, depending on its age, to become fully tender. It is sold in Asian grocery shops, especially Indian ones, and by mail order; the hulled, split form is pale and a different product.
There is no true substitute: beluga lentils look similar and are also earthy, but they stay separate and never give the silky, creamy body that defines the dish. If you use them anyway, cook them for less time and thicken by mashing part of the pot.

Nepal
A Nepali set meal: rice in the middle, dal, chicken curry, aloo tama and pickle