Mix everything very well... Rub the flour inbetween your palms to incorporate the vanaspati well for 3 to 4 minutes.. after this step the flour should resemble bread crumbs.. press down a handful of this flour in your palm, it should form or hold the shape.. it should not crumble meaning vanaspati is well incorporated... Add 4 tablespoon of water and begin to form a dough ball adding more water as needed.. I added 4 +2 tablespoon water in total..

Dough has to be firm, stiff and not sticky.. cover and rest for 25 to 30 minutes..

Heat 1tbsp of oil in a pan.. next and cumin seeds.. when the seeds begins to splutter and add bay leaf, chopped ginger, chopped green chilli.. saute for 20 to 30 seconds.. optional - you can also add cashews.. and then add cooked and mashed potatoes..

Add spice powders.. mix well 2 to 3 minutes until potatoes blend well with spice powders.. finally add chopped coriander leaves.. taste test this and adjust salt if needed..

After 30 minutes knead the dough for another 2 to 3 minutes.. the dough has to be stiff yet and not soft.. oil the counter or rolling board place the ball.. roll it to a oval shape even layer.. it has to be slightly thick and not to too thin.. cut it in the centre to make 2 parts.. apply water with your fingers over the straight edge..

Stick the edges to seal well.. make sure your samosa sealed well.. pinch and press down on the edges very well to seal them.. this will give you a perfectly standing samosa..

Heat a pan with oil for deep frying.. the oil should be moderately hot and not very hot.. add a small portion of dough to the oil it has to raise slowly and the oil must not to be bubbling or sizzling a lot.. you should see only tiny bubbles.. this is right temperature..