A cornichon is the French version of a gherkin. You'll find these small, tart pickles in gourmet grocery stores; otherwise, gherkins will work just fine. Or, if you have capers on hand, you may substitute 1 tablespoon drained capers for the pickles. Make this potato salad recipe up to two hours ahead.
View Recipe: Potato Salad with Herbs and Grilled Summer Squash