I remember reading a story from the 1950s or maybe early 60s by an American writer, takes place in I think rural New England, I believe at a summer home. The plot revolves around a youngish mother and her small son. I think the dad was not present (off working?) and is written in third person omniscient, but the mother is the POV character. In the course of the story it’s revealed that the nanny/housekeeper has made some anti-Semitic remarks in the hearing of the boy, not knowing that the family is Jewish. I believe it ended with the mother comforting the boy.
Ring any bells?