Very easy. Just make your first cup of coffee. The very first character wants an Expresso. So...
Serve your drink and achievement unlocked.
What? Espresso?! Yeah, thats what I wrote. I didn't make a mistake you did. Well I'd edit it, but TA doesn't have a edit button. So who is wrong now? What? Me still. I'm outta here. Sheesh.
YOU CAN'T GET THIS IN ENDLESS MODE