After a little confusion — the counterwoman thought I was after the majarete — I secured one of its unlabeled neighbors ($1.25) from the bottom shelf of the display case. "Dulce de leche" was the only name she could give to it, but though this Dominican pudding had that familiar caramelized-milk flavor, as well as a few hidden raisins, it was coarse rather than spreadable. A precursor, perhaps, to concon of milk?
Update: Apparently this is simply a granular variant that's common to the Dominican Republic and its neighbors. I've since seen it labeled "dulce de leche" at the Cuban hotspot El Palacio de los Jugos, in Miami.
La Goya Bakery
1318 St. Nicholas Ave. (at West 176th St.), Manhattan
917-284-7524