Butter mochi is a traditional Hawaiian treat, it is made with a high glutenous rice flour called Mochiko Flour. Like most Hawaiian food Butter Mochi is a fusion of different cultures who most likely met on in a plantation village. My guess on how butter mochi has come to be is that it is a hybrid of Japanese Mochi and Filipino Bibingka.
Musubi is a thick layer of rice with a slice of Spam that’s been cooked in a sweet-ish sauce and wrapped in a thin slice of nori. Much like many dishes before it, the Japanese immigrant population got hold of SPAM and Musubi was born. Some people say it’s “spam sushi” which, I guess it is.