Wash potatoes and pressure cook both potatoes and mochai in 2 separate containers for 2 whistles.
Transfer the mochai to a colander till the water gets completely drained away.
Peel the potatoes and cube them or you can also crumble them into big chunks with your fingers.
In a mixie jar, take coconut, garlic pods, turmeric powder, dry chilies, cumin and fennel seeds.
Grind it to a coarse paste using 1 or 2 tsp water and keep aside.
Heat a pan with oil. Add mustard seeds and let it splutter. Add curry leaves and let it also splutter.
Add crumbled potatoes, mochai, ground paste, salt and mix well.
Simmer the flame completely and let it cook till all the moisture evaporates. Keep mixing in between to prevent the curry from sticking to the bottom.
This should take 5 to 7 mins. Take off fire and transfer to a serving bowl.
Potato Mochai curry is ready.
Serve hot with sambar, rasam or curd rice.