One of the benefits of being friends with a food writer and cookbook author is you know you’re getting honest criticism. But when it came time to come up with a flavor that did justice to her talent, I took my time. The result — a blend of Meyer lemons, the classiest commonly available citrus (second classiest: blood oranges; third: key limes) and crème fraîche — turned out well. The zest in the ice cream base slightly heightens the flavor of the curd. You can swap out regular lemons and sour cream for those two, but it won’t be as sophisticated.