From the Taipei Times write-up:

...Biff's Pitas, a street stall that opened one month ago and has seen customers lining up to dig into some of the tastiest pitas in town. The owner, who calls himself Biff Cappuccino, is a Canadian who has lived in Scotland, Nigeria, Ireland, Uganda, the US and has spent the last two decades in Taiwan.

...My father had a tradition where he would never cook the same meal twice in one month," Biff said. "He loved to experiment preparing foods from different countries." Though the menu at Biff's is fixed, he said he applied his father's ethos by experimenting with his cooking methods before arriving at his current creations, which reflect his interest in Asian flavors.

...The proprietor says he can make his sandwiches as spicy or mild as the customer wants. My favorites are the Madras curry chicken and the Mexico Jalapeno chicken, extra spicy.