Given the heavy influence that East Asian has had on Hawai`i's culture, it's not surprising that local people eat a lot of mochi. However, the sweet dishes we make from rice are a far cry from anything you'll see in East Asia. You can find recipes for over a hundred local-style mochis in Jean Watanabe Hee's Hawai`i's Best Mochi Recipes (Mutual Publishing, 2000), which is locally published but available elsewhere from a variety of online bookstores (though it seems to be out of stock at Amazon).
Though Hawai`i mochi (as indicated by the name itself) is derived from primarily from Japanese origins, its ingredients often are closer to those found in Southeast Asian snacks, particularly the "kueh" of Malaysia and Singapore, neither of which has sent a significant number of emmigrants to Hawai`i. It guess this is a case where similarity of arises from climate and availability of ingredients, not from any direct cultural influence.
There are two basic categories of Hawai`i mochi: the kind you buy in a bakery or store and the kind you make at home. In general, any kind of mochi that requires pounding, rolling, or filling is going to be bought outside - we're lazy, so who's going to spend hours on something like that? The kind you make at home is usually made from rice flour and baked or steamed in a pan, butter mochi being the most popular example.
Store-bought mochis range from very traditional Japanese varieties to "only-in-Hawai`i" local adaptations. You can find mochi everywhere, from specialty shops, to bakeries, to supermarkets. The biggest local manufacturer is Fujiya, which has been in business for about half a century, while Kansai Yamato is another producer whose products get sold around the island. Some of the more popular local products include extreme variations on Japanese daifuku (a round mochi filled with sweet azuki beans) and chichidango (a rectangular-shaped mochi). Some of the more distinctive and popular Hawai`i versions of daifuku are one filled with peanut butter, another filled with strawberries and white beans, and a purple version filled with kulolo (sweetened mashed taro with coconut). Chichidango come in all sorts of flavors, including fruit flavors such as mango, banana, and blueberry, as well as haupia (coconut pudding), poi (taro paste), purple Okinawan sweet potato, coffee.
Here are a picture of two store-brought products, a haupia chichidango from Fujiya, and a kulolo-filled taro daifuku mochi from Taro Brand Poi. The haupia chichidango is only mildly coconutty; you can still taste the mochi rice. The taro mochi, on the other hand, tastes more of taro and coconut, though the mochi provides a nice texture contrast. Its purple outside is due to food coloring (not purple rice!) but the kulolo inside is naturally a bright purple from the cooked taro.
As I mentioned, homemade mochis tend to be much simpler and made from rice flour, since only a few intrepid souls would try to pound their own. And unless you practice, it's dangerous for the guy who has to turn the mochi while the guy with the huge mallet is on the upswing!
Butter mochi is by far the most popular of the homemade types. It's basically baked in a pan and cut into squares or rectangles, like a brownie. There are lots of variations on the recipes, but most call for mochi rice flour, coconut milk and/or evaporated milk, white and/or brown cane sugar, eggs, and butter. Some people add baking powder, though it's not really necessary and makes it more "cake-like". I like to sprinkle some kind of crunchy thing on top, like shredded coconut, sesame seeds, pine nuts, or macadamia nuts. I once made a dark chocolate butter mochi with pine nuts that I thought was pretty devastating, but nobody ate it. Butter mochi is best eaten slightly warm, or else it can turn rubbery on you.
Here's a picture of the butter mochi I made for New Year's Eve. It's a plain one made with coconut milk, white sugar, and sesame seeds. If you look carefully, you can see it has a crust, which differentiates it from almost all the mochis that you can buy in the stores. Arguably, that's the best part of the deal.
