While it's currently limited to just one designated drink, you can now tell Alexa to order said drink from one of the last ten stores you visited by simply saying "tell Starbucks to start my usual order." You will need your Starbucks account linked to your Amazon account. You can also ask Alexa to tell you your Starbucks Card balance.
Users are already chomping at the bit for added features, like selecting a new drink via voice, new location, or having your order started at a certain time (as opposed to right as you order it), and the development team has already responded, saying that updates are on the way. Good luck getting those hooks out now!