Heat oil in a pan and when the oil becomes slightly hot add mustard seed and let it splutter.
Add ginger, green chilly and sauté it for a few seconds.
Add finely chopped onion and sauté till it becomes soft and translucent.
Now add frozen peas, carrot, mix it well and cook for 2-3 minutes on medium flame.
Lastly add boiled, mashed potatoes and all the spices mango powder, red chilly powder, garam masala, cumin powder, salt, freshly chopped coriander leaves and mix it till all the spices get blended well.
Potato mixture is ready, let it cool down for some time.
Once the mixture cools down to take a generous amount of mixture, roll it in your palms and make it into an oval shape. Repeat the same process for the remaining potato mixture. Size of the potato rolls depend upon the size of bread.
Trim the edges of bread slices.
Take a bowl filled with water and dip one bread slice lightly in the water just for a second just to make it moist. Take out the bread slice and press it lightly between your palms to remove the excess water.
Now place oval-shaped potato rolls in the center of the wet bread slice, bring the edges together and wrap the bread completely all around. Seal the edges tightly so that filling does not come out and roll filled bread into oval shape. You can also roll it into round shape.
Repeat the same process to make rest of the bread rolls.
Heat the oil in a pan on medium high heat, once the oil becomes hot enough, drop the bread rolls slowly into the hot oil, taking care not to overlap them. Do not overcrowd the pan, fry in batches.
Fry bread rolls on medium flame till it turns golden brown and crisp by turning occasionally. This would take around 2-3 minutes.
Take them out on the absorbent paper to remove excess oil.
Serve hot with any green chutney, tomato sauce or chilly sauce.
You can use multigrain bread or brown bread to make bread rolls Oil should be hot enough otherwise the bread will soak lots of oil.