Firstly, blend the tomatoes to a smooth paste and keep aside.
In a mortar pestle, add garlic, ginger, green chilly and crush them to a coarse paste. Keep aside.
Heat oil in a pan.
Add cumin seeds and fennel seeds.
When the seeds start crackling, add ginger-garlic-chilly paste and saute for few seconds.
Now add asafoetida and chopped onion.
Add salt and cook the onions till they turn golden brown in colour.
Add tomato paste and cook for around 5 minutes.
Add turmeric powder, red chilly powder, cumin coriander powder, garam masala and mix well.
Add chopped potatoes and mix well.
Add a cup of water and cover the pan.
Cook for 15 to 20 minutes on low flame or until the potatoes are cooked.
Check the consistency of gravy.
Add water if required, as per the desired consistency.
Crush the roasted kasuri methi and stir into the gravy.
Garnish with chopped coriander leaves
Serve hot with puris.