This is called pineapple bun, which is a local food in Hong Kong. Don't get it wrong! It is not made of pineapple in anyway. It is called pineapple bun because the crispy topping make it looks like a pineapple. Serving with a big piece of butter, pineapple bun is the best companion with milk tea for breakfast of afternoon tea.
IMO, this pineapple bun is more a fusion food in which I still prefer the local version. In your area, does Starbucks serve any local food? How does it taste?