Take 2 - 3 tomatoes, 1 onion and 1/2 cup Moong dal and keep them in a pressure cooker and cook well.
Make seasoning with cumin seeds and mustard seeds.
Add chopped green chilies and fry well
Add cooked dal and vegetables in that.
Add one spoon of sambar powder.
Bring it to a boil and serve this tomato masala with chappati or puri.