Undoubtedly my favourite dish I encountered in Bangladesh was phuchka (known elsewhere as panipuri), tiny crispy poori-like breads filled with a delicious mixture of spiced beans, chunks of potato, diced shallots, chopped fresh chili and cilantro (illustrated above, at the top). The phuchka are spicy, fresh, sour, and are small enough to be consumed in one go. The beans used were most likely a type of chickpea, but actually reminded me of the tender gula ärtor Swedes traditionally eat in their ärtsoppa every Thursday.
A variation on the dish, consumed in Khulna, southern Bangladesh, did away with the act of stuffing altogether and simply served the crumbled bread over the bean mixture, which also had slices of hard-boiled egg:
I believe this version is called chatpati, which was also the name of the shop. Regardless, an essential part of this dish appears to be a sour tamarind-based, watery sauce/dip, which was served with both types.