In a mixing bowl mix together potatoes, onions, green chilly, coriander leaves, dry mango powder, chat masala and little salt.
In a separate bowl mix together besan, salt, red chilly powder and add little water at a time and make a batter (like pancake). Mix it for 3-4 minutes till batter becomes little fluffy and keep it aside.
In a separate bowl mix together all purpose flour and water and make a thick paste. Now take tortilla or chapati. Put generous amount of potato mixture on one side of the tortilla or chapati.
Put all purpose flour paste on the rim of the chapati or tortilla. Roll it from one side to another and make a tight roll.
At the edges put some more all purpose paste and turn the edges as shown in the video. Let it rest for few minutes so that edges get completely sealed.
Heat the pan at medium heat and add oil. Dip the roll in besan batter and get it nicely coated from all the sides.
Heat 3 tbsp oil in medium hot pan. Put rolled tortilla or roti pakora in the oil. Cook it from both the sides till roti pakora become golden brown and crispy.
Once done take tortilla pakora out on paper towel. You can serve roti pakora as it is or cut it in two pieces and serve it with your favorite dip.