In a big mixing bowl, take flour, baking soda, and baking powder together. Mix it well once, then add cold butter and mix it with your fingers. Mix the butter and flour till the flour turns into bread crumbs like texture.
Now add the curd and make a soft dough however don't knead the dough. Cover and set aside for half an hour.
To make the sugar syrup. Take a pan, add sugar and water and bring it to a boil, then reduce the heat to low and boil till the syrup is almost one thread but has not reached the one thread consistency yet. (If you touch the syrup with your fingers it should stick to your fingers but should not form a thread.)
Add in cardamom powder and remove from the heat and set aside. Make small balls out of the dough and lightly flatten them on your palm and make a deep dent in the center.
Heat oil in a medium heat, slowly drop the balushahis one by one into the oil, fry 4 to 5 at a time but don't crowd the pan.
Fry the balushahis till they turn brown on one side then slowly turn the other side and fry till it turns golden on both sides. Remove from the oil and drain them on a kitchen towel.
Dip this fried balushahis into the sugar syrup and remove them immediately. (Don't leave them in the syrup for a long time as they become soft, so note to remove quickly.)
Garnish with chopped pistachios and serve.