Knead a smooth dough by adding the flour, salt, ajwain, oil and water together. Let it rest in a closed vessel for 5 mins.
In a pan, heat oil then add the chopped cashew nuts along with green chillies and onion. When it turns golden, add in the boiled potatoes which have been cut into cubes. Add the salt, chilli powder, chaat masala, dhania-jeera powder and mix well. Do not let this burn.
Add the chopped coriander leaves. Also dry roast the coriander seeds and saunf, then coarsely crush it and add it to the masala. (This will enhance the flavour).
Mix all the ingredients well and let it cool . Your filling is now ready.
Now form small balls from the dough and roll it into thin chapatis. Cut it into half. Now hold the half cut chapati and apply water on the sides. Fold it into a cone and seal.
Fill the cone with masala and apply water on the open sides which has to be folded. Make a pleat on the opposite side of the joined part. Seal all the sides and you will get a triangle shape, ensure that its sealed well.
Heat oil and deep fry these samosas in hot oil with a low flame till all the sides turn golden brown.
Serve samosas with chutney or ketchup.