Back in the Philippines, “Ube” is the purple yam, that is so famous as a dessert, jam or ice-cream. I love it and the closest “food” that I can get is this Japanese bread – with the purple sweet potato or in Japanese, “Murasaki Imo”, literally translated as Purple Potato. Hontou ni “oishii desu” (silent u) - Japanese bread and cakes are not that sweet . 
Wow that looks absolutely tempting! Is that purple thingy the same as taro? I love all sorts of bread, but my fave is pinagong in Quezon Province.
Thank you AJ
Take care.