Wikipedia
A (also known as melon pan, melon bun or melon bread) is a type of sweet bun from Japan, that is also popular in Taiwan, China and Latin America. They are made from an enriched dough covered in a thin layer of crisp cookie dough. Their appearance resembles a melon, such as a rock melon ( cantaloupe). They are not traditionally melon flavored, but in recent times it has become popular for manufacturers to add melon to melon bread. Variations exist, including some with a few chocolate chips between the cookie layer and the enriched dough layer, and non-melon versions flavored with caramel, maple syrup, chocolate, or other flavors, sometimes with syrup, whipped or flavored cream, or custard as a filling. In the case of such variations, the name may drop the word "melon" ("maple pan") or may keep it despite the lack of melon flavor ("chocolate melon pan").
The name has a bilingual etymology, since melon is a loan word from English, while pan is from the Portuguese word for bread.
In parts of the Kinki, Chūgoku, and Shikoku regions a variation with a radiating line pattern is called "sunrise", and many residents of these regions call even the cross-hatched melon pan "sunrise".
Melonpan and pineapple bun from Hong Kong are very similar. By comparison the Japanese style is lighter in weight and taste, slightly dryer and has a firmer outer layer (including top cookie crust) which resists flaking unlike its Hong Kong counterpart, which should be treated with care as the top cookie crust tends to flake easily. The Hong Kong version is also moister and is generally soft on the outside and inside and has a stronger butter flavour.
melon buns melonpan.jpg|Melonpan variety containing chocolate chips