Soak spilt peas 12 hours or overnight, then drain.
Bring water to a boil and add peas, sliced onion and green chilies.
Cover and simmer for 1 hour.
Heat 1 tablespoon of the vegetable oil and fry the coriander, chili powder, cumin, turmeric and asafetida for 2or 3 minutes.
Add to the simmering peas, along with the green pepper and tomato.
Put in salt. Simmer1/2 hour.
In remaining 1 tablespoon of oil, fry the fenugreek and mustard seeds until they crackle.
Add onion and brown lightly.
Add to the spilt peas.
Stir in lemon juice.
Serve with rice, idlis or dosas.