To make sweet chutney

Soak tamarind in 2 cups of warm water for 5 mns. Heat a heavy bottomed vessel, add the tamarind along with the water and bring to a boil. Turn off heat and cool. Once cool, grind this tamarind mixture along with dates to a fine paste, adding very little water. Strain through a sieve and pour this tamarind-date paste back into the heavy bottomed vessel.

Cook on slow to medium flame for 2-3 mns. Add the grated jaggery and allow it to melt and blend well with the tamarind date mix. Continue to cook till it becomes a thick pouring consistency, approx 15-18 mns.

Add chilli, cumin, saunf powders and salt to taste and combine. Turn off heat. Even if the chutney is thick, its fine. Once cool, refrigerate and use as required.

To make green chutney

Wash pudina and coriander leaves thoroughly and allow the water to drain. Grind the mint leaves, coriander leaves, salt, sugar, lemon juice and green chillis to a fine paste, by adding 2 tbsp water. Remove into a bowl. Refrigerate until use. It keeps well in fridge for 2-3 days.

Assembling the puris:

Crush the top of the puris to place the fillings. Fill each puri with the mashed potatoes, then add chopped onions. Fill each puri with sweet and green chutney, followed by the yogurt. Sprinkle the sev and roasted cumin, chilli and chaat masala (if using) powder on top of each puri. Garnish with chopped coriander leaves. Serve immediately, otherwise the puris will become soggy.