I thought the optional sour cream in the strawberries Romanoff recipe was an attempt to re-create the flavor of whipped cream in the days before refrigeration. I’ve since discovered that Carême made two versions: one with plain whipped cream and one with sour cream added. The former was designed to appeal to French audiences, the latter to appeal to Russian audiences. Americans came along later and added ice cream. I’ll leave it up to you to determine the best fit for your table.