Its a freeking coffee!
I once went into a Costa and asked for a large coffee an an almond biscuit . The guy serving me then said, "do you mean a....(some Italian Bo***cks") .. and a biscotti, sir?" with so much disdain that clearly he thought I was some kind of low pond life.
It made my blood boil! I am too polite to have retorted "Just give me the coffee and biscuit, ponce." I am the paying customer, and Costa is hardly fine dining,
So my word is biscuit or if you want to be an utter knob "biscotti".