Poke holes around the russet potatoes with a knife. Boil them in 3 cups of water for 30 minutes. Thereafter set the potatoes out in a colander to cool down and dry out. Peel the potatoes once they cool down and mash them in a mixing bowl. The mash does not need to be smooth.
Pour 1 tbsp oil in a saute pan on medium heat and add 1/2 tsp turmeric. Add diced vegetables and saute for 10-15 min. The primary purpose of this step is for the vegetables to lose their raw taste. Once the vegetables cool, add them to the potato mash.
Add garam masala, red chile powder, salt, remaining turmeric, raw mango powder and ginger to the vegetable, potato mix. If you don't have raw mango powder, replace with a tsp of lime juice. Set aside.
In a large bowl, take about 2 cups water. Immerse piece of bread in it. Stir it around with a fork and make sure it remains in water for 5-10 minutes. Now take the bread and squeeze it between the palms of your hands. Make sure that you squeeze the bread dry. Combine this soaked bread with the potato, vegetable mixture and mix well.
Now make patties that are about 3 inches in diameter and 1/2" thick out of the potato, vegetable mixture. You'll get about 7-8 patties. Now heat a nonstick pan, pour 2 tbsp oil in that pan and place 4 patties on them. Heat them till they get a brown, crunchy exterior.
Repeat with the rest of the 4 burgers.
I froze a couple of patties in an airtight container in the freezer. And heated them in a toaster oven after 2-3 days. Tasted lovely!
In order to grill these burgers, pre-cook them fully on a non-stick pan as mentioned above. Freeze them, throw them on the grill at your BBQ.
For the burger assembly
Pour oil on a nonstick pan. Roast both sides of bun till they get a golden sheen.
Spread cilantro chutney inside the bun. Place the potato patty and place 2 slices of tomato and onions. Sprinkle chaat masala (salt and pepper is fine too) on tomatoes and onions. Close the bun and eat away.
Feel free to eat the patty on its own too with cilantro chutney. Actually I insist!