The gravy for this dish is more on the liquidy side with the slight thickness imparted by the starch released by the potato while cooking. But if you like to have this dry that's an option too. Just add less water and let it evaporate while cooking.
Now to the recipe...
1-2 tbsp oil
1/2 tsp mustard seeds (rai)
1 tsp cumin seeds (zeera)
2-3 green chillies slit vertically (or to taste)
10-12 curry leaves
pinch of asafoetida (hing)
1 medium sized onion cut in juliennes
3 small potatoes cut in slices/thin wedges
2 tomatoes cut in slices
1/4 tsp turmeric powder
1/2 tsp red chilli powder (or to taste)
1 tsp salt (or to taste)
2 tbsp coriander leaves finely chopped
In a vessel, heat oil and once hot add the mustard seeds. When they begin to splutter add the cumin seeds and asafoetida. Saute and add green chillies and curry leaves (be careful as the oil will splutter high on adding these). Saute for a few seconds and add the onions and cook till translucent. Then add the potatoes and cook for about 5 mins.
Now add the turmeric power and salt. Mix well and let the potatoes cook for about 5 mins. Then add the red chilli powder and mix again. Cook for another 5 mins to allow the masala to cook. Then add the tomatoes and 1 cup (or as required) of water. Mix everything well, cover and cook on medium low heat for 10-15 mins or until the potatoes are done. Add the coriander leaves and mix.
That's it, our super simple and extremely delicious Onion Potato Tomato Curry is ready. Serve it hot with some roti/chapati or rice. Enjoy!!