In Search of Romanian Pastry, Galuste cu Prune
The Czech restaurant Zlata Praha, in Astoria, used to make plum dumplings. They even served them on the street at the Czech Independence Day Festival:
Unfortunately, they're out of business, and Olde Prague Tavern, which recently opened at that location, seems destined for a drinking-food menu. Milan's, the Slovak restaurant in Greenwood Heights, has served these, too, though your friend would do well to call before heading down. When inquiring at Milan's, or at any of the other Czech establishments in the city, she might also ask for plum dumplings by their Slovak names, slivkove knedlicky or slivkove gule. Best of luck to her!