To succeed in this quest, you need to do the quest Preparation for the Dragon Quest. In this quest, the novice Avanti will ask you to search for one book for his master. When you found it, on one of those big desk one floor below is Avanti, he gives you the recipe for Auralia and you just have to go back to her. She gives you the recipe and asks for help for a missing ingredient. If you can find it she will join your party.
This didnt work for me. i had to continue with the main quest till i got to Tallon. there i found leprechaun. when you talk to him and play his game for a while, he will figgure out the recipe for you