First fry the capsicum lightly with a teaspoon oil and keep aside. Take a non stick pan ,heat oil add few mustard seeds and fennel seeds, when they pop add chopped onions and curry leaves.
Sprinkle little salt and saute it , fry the onions lightly. Add the potato and turmeric powder, mix it well and fry .
Turn the heat to low,close it with a lid and cook. Open the lid for every 1-2 minutes ,give it a stir and fry well.
Once the potato get half cooked or becomes little soft add the fried capsicum and all dry powders, salt as needed and mix well.
Close the lid and cook till the raw smell of the masala goes . No need to add water ,cooking in low heat with closed lid will make the potato soft and tastier.
At last add the chopped coriander leaves and serve hot . It goes well with chapathi,dosa,sambar rice,curd rice.