The first time I had passion fruit I was in Hawaii and ate it right from the tree, where it was perfectly ripe. I fell in love with its beautiful tart and floral flavor. You can usually find passion fruit in Asian markets or specialty food stores. Sometimes it can be a bit on the pricey side, but I think it is well worth it.
While not everybody chooses to eat the seeds, they add a lovely crunch to this shake. If you are using a blender, the seeds will break down, and you can use a straw to drink this shake. If you use a milkshake maker, like I did, the seeds will stay whole and then a spoon will be your best bet. Either way, you are in for a treat!
Excerpted from Malts & Milkshakes, by Autumn Martin (St. Martin's Press, 2013)