There are a number of Honolulu Cookie Company stores around Waikiki, but they all have a section of the store where you can serve yourself with free bite-sized samples! Shamefully, I never made a purchase (as tempting as the stores are) because I have to admit they aren't the *best* shortbread biscuits I have tasted. I believe they would make fantastic gifts though! They sell gift boxes and beautiful cookie tins. There's also heaps of flavours which makes it interesting.
I am guilty of coming here a few times and taking one or two samples. Luckily the staff must be used to it as they generally leave you alone and let you peruse the store without hassling you to buy things.