For the best flavor, use high-quality mayonnaise and fresh tarragon. If you don't have fresh tarragon, you can substitute 1 tablespoon of dried tarragon, but the flavor will be more intense. To make the deviled eggs ahead of time, prepare the filling and store it separately in an airtight container in the refrigerator for up to 2 days. Fill the egg whites just before serving to prevent them from becoming soggy. Experiment with different types of mustard, such as Dijon or whole grain, to create your own signature flavor. For a spicier kick, add a pinch of cayenne pepper to the yolk mixture.