Wash and soak chana dal for 4 hours. Drain and take them in a sauce pan, cover with water and cook for 5 mins till it is cooked completely. Drain and set aside.
Now heat oil in a pan, add mustard, urad dal and let them sizzle. Add in asafoetida and mix well.
Add in ginger, green chilli and curry leaves and let them sizzle.