Heat oil in a pan over medium heat and sauté the coriander seeds, cumin seeds and asafoetida. Next, add the ginger paste, green chilies and peas and cook for a minute or two.
Add in the mashed potatoes and continue cooking for a few minutes, mixing occasionally.
Add the spices and salt and give it a good mix.
Take the pan off heat and mix in the chopped cilantro.
In a large mixing bowl, combine the all purpose flour with a bit of salt, carom seeds and oil.
Add some water if needed and knead into a dough that's not too soft. Make dough balls and roll them into thin ovals like this.
Cut each oval into a half and use your fingers to grab each sharp end of the dough towards the top.
Press the corners together and create a pocket that looks like this.
Fill the pocket with the samosa mixture and bring the top together towards the other end, pressing down on it to seal it shut.
Layer on a baking sheet lined with parchment paper and grease with some oil. Bake for about 15-20 minutes at 180 C, flipping them midway.
Notes
Make sure you maintain even thickness when you're rolling the dough. This will help the samosas get that perfect golden brown crunchy and crispy texture on all the sides.
To make the samosa dough extra crispy, you can reduce the amount of all purpose flour you're using, and add some rice flour instead.
Make sure you allow the potato filling to cool down completely before you start to make the samosas. This will help the excess moisture dry up and the mixture will be easier to handle.
You can also use a half-and-half mixture of all purpose flour and multigrain flour wheat flour to make the samosa pastry slightly higher in fiber.
Make sure the samosa dough isn't too soft. If it does seem soft, add a bit more flour and knead it again until it becomes stiffer.
To make cheesy samosas, you can add some shredded mozzarella or cheddar cheese to the filling!