Take the plain flour in a mixing bowl, sprinkle in the salt, add the ghee and 2 tbsp oil. Mix well till it is well incorporated into the flour.
Make a well in the flour, add 1/3 cup of warm water. Gently mix the water and flour and start kneading with your fingers.
Gradually add more warm water as needed till the dough becomes firm but soft and pliable when rolled. Cover with a damp cloth for 30 odd minutes.
Divide the dough into medium balls, using a rolling pin, roll out each dough ball to an oval shape. (for detailed steps with pictures please check my Phulkopir Sinagara Recipe)
Cut the oval diagonally. Brush the edges with a little water. Bring the straight edges gently together to form a hollow cone.
Hold the cone in your hand, fill it with potato stuffing.
Now press the open mouth of the cone and give it a double fold to seal it. Your singara is now ready to be fried.
Heat the oil and ghee over a low flame till just warm. (Take care to not over-heat the oil. If the oil is very hot, the outside of the singaras shall brown very quickly while the inside shall remain uncooked.)
Fry the singaras till golden brown on all sides, carefully turning them in between. It takes 20-25 odd minutes to fry a batch. Remove from oil, keep aside over a kitchen towel.
Serve hot.