Heat one tablespoon of oil in a frying pan over medium high heat. Add the chopped onions, and saute until they are softened.
Mix the turmeric and chili powder into the frying pan and remove the pan from the heat. Stir the mashed potatoes and cilantro into the frying pan; stir to mix well.
Sprinkle a few drops of water onto each slice of bread. Flatten the bread gently. Spoon 1/4 of the potato mixture onto the slice of bread. Roll the bread into a cylinder. Seal the edges together by pinching the ends with your fingers, use more water if it is necessary to keep the bread sealed. Do the same with the remaining 3 slices of bread.
Pour the three tablespoons of oil into a large frying pan or wok. Heat the oil to a high heat. Place the bread rolls into the hot oil and fry until crispy.