Walking down Knickerbocker Ave., along Maria Hernandez Park, I saw a gentleman sitting by the curb before a small barrel that contained a smaller tub; with a bowl scraper, he slathered a sunny yellow substance into serving cups.
"Mexican ice cream," he told me, though it seemed more like a creamy ice (small, $1). (I've since learned that "nieve" is the usual name — literally "snow," apparently "sherbet.") Though I didn't linger long enough to get the whole story, I had the impression that he's associated with an established dairy-products business — if true, other days might bring other flavors.
Mexican ice cream vendor
Near 276 Knickerbocker Ave. (Willoughby Ave.-Suydam St.), Bushwick, Brooklyn