For Cover:

Mix all the ingredients (salt, oil) except water.
Add a little water at a time.
Pat and knead well for several times into a hard pliable dough.
Cover it and keep aside for 15 minutes.

For Stuffing :

In a bowl add mashed potatoes and all dry masalas (salt, chilli powder, coriander seeds,fennel seeds) and green chilles, ginger,green peas and Mix well.
In a deep pan or wok take 2 tbsp oil. Heat it up then add mustard seeds, turmeric powder.
After crackling add above mix of potatoes. Fry for 2-3 minutes.
Add coriander and keep aside.

To make samosas :

Make small rolls of dough and roll it into a oval shape.
Cut it into two parts like semi-circle.

Now take one semi circle and fold it like a cone. Use water while doing so.
Place a spoon of filling in the cone and seal the third side using a drop of water.

Serve samosa hot with tamarind chutney.