Hello Bgirl and welcome to Chef Talk. I've always wanted to taste a butter tart; they're a Canadian original, right?
As Cakerookie said, the Pastry and Baking Forum (the one for professionals) is a good place to post your query and begin your exploration. We have many professional bakers among our members, and I'm sure you'll have an answer. It might be worth mentioning your location if you're outside the U.S.
Good luck! Enjoy the board and come back often.
Regards,
Mezzaluna