I usually boil some extra pototoes whenever i get time and keep them in the fridge so that i can make this almost instant potato gravy .
chopped boiled potatoes to the size you desire.
take a kadai and put oil in it. add mustard seeds , cumin seeds, hing, green chillies and curryleaves , when the whole thing splutters add finely chopped onions stir add the chopped potatoes, and let the whole thing cook for some more time till the masala incorporates with the potatoes.
add a little chilli powder, haldi powder, and dhania jeera powder .
stir and smash some potatoes in the gravy to get a thicker and tasty gravy.
add salt and a pinch of sugar , garnish with lots of coriander leaves finely chopped.