You can pressure cook the sweet potato by keeping it inside a vessel without adding any water. Cook for 3 whistles. The cooked sweet potatoes should be firm and not mushy.
You can cut them into 4 pieces and boil them in a pan filled with water. Boil them until they are cooked and firm.
In a bowl add the ingredients given under the heading "to marinade".
Combine them well and let this sit for 5 minutes.
In a pan add the sweet potato mixture and let this roast in a small flame for 3-4 minutes.
Alternatively, you can deep fry this too or oven roast this too.
Take this out from the pan and spread it on a plate.
Sprinkle some green chutney and sweet chutney.
Beat the yogurt well and sprinkle some on this. Let the yogurt be chilled and thick.
Sprinkle jeera powder, chaat masala, and red chili powder.
Sprinkle with sev and garnish with coriander leaves.
Serve immediately.