Ingredients 

2 big potatoes
2 tomatoes
Half kg green peas
1tsp mustard seeds
Half tsp cumin seeds
Asoefetida a pinch
1 tsp chilli powder
Half tsp turmeric powder
A pinch of garam masala
1 cup coconut milk 
Small piece of jaggery or half tsp sugar
Salt 

Method 

Heat 1tsp oil in a kadai, put the mustard seeds in it, after they crackle add cumin seeds and asoefetida then put in the chopped potatoes, tomatoes and green peas.
Add 2 cups of water and the turmeric powder,chilli powder,jaggery (or sugar) and the salt.
Let it cook till the potatoes are done.Then add the coconut milk (if powder is being used, first mix it in cold water and then add to the hot mixture) bring it to a boil and put it off. 
Garnish with finely chopped corriander leaves. 

Serve hot with rice or rotis.