Heat oil in a thick bottom pan. When hot add mustard and cumin and then the turmeric. When seeds start to splutter add the asafoetida.
Add the onions and fry for a few minutes.
Add the chilli and ginger paste. Fry again for one minute and add garam masala.
Add the tomatoes and cook until they blend into the rest of the sauce.
Reduce the heat and add the yoghurt, stirring continuously.
Add the peas, cover and cook until peas are tender. Add water, little at a time, if more gravy is required.
Brown 1 inch square paneer pieces in a deep or shallow fryer. If you do not want to use any oil, dry roast the paneer pieces on a non-stick frying pan.
Add to the main curry. Simmer for 5 more minutes.
Garnish with the coriander before serving.