Up an alley just next the Khoai My stall at 25 Nguyen Binh Khiem I sniffed out a Che seller. Che are the ubiquitous sweet desserts sold all over southern Vietnam, but rarely found in the north. Normally consisting of various combinations of tapioca, beans, sweetened coconut milk, fresh fruit and sugar. They're a dentist's nightmare, but a pleasant and no doubt healthier alternative to a Cornetto.
I ordered a Che dau van (Haricot bean che). Actually that's a complete lie. I tried to order a Che chuoi (Banana and tapioca che), and clearly failed. And of that I am glad. The Che chuoi, and pretty much any Che I have tried, tend to be a tad heavy. So I was pleased when this 1,000VD bag of beans didn't drop anchor in my stomach and refuse to budge for the rest of the day. One is light enough to keep you on the move, but go for two and you'll be needing a nap.
I strongly recommend Che and it's worth tracking down a street seller who'll flog you the stuff. Or sample the excellent selection served at one or two of the stalls on Ben Thanh Market.