Are you a phenomenal baker, famous for your delicious homemade treats? Then you can call yourself the doyenne of cupcakes. A doyenne is an undisputed expert at something.
Since 1905, doyenne has been used to mean "leading or senior woman in a group or society," from the French doyen, "senior member." While you can refer to any elder as a doyenne (like the leader of your Girl Scout troop), these days it's most commonly used for someone who's considered one of the most respected in a field. Oprah Winfrey has been called the doyenne of daytime TV more than once in her life.