The current Utne magazine has a recipe for Xocoatl from a group of folks at Chocosuisse. According to the article, Chocosuisse researched the Aztec chocolate drink and are attempting to recreate it with this recipe.
They offer an interesting sounding concoction of chocolate, crushed almonds, milk, honey, lemon juice, rum, arrack (a cocount palm liqueur which I've obviously been missing out on), allspice and ginger. (What? No cinnamon? No chiles? No vanilla?)
They go on to describe a method of making the drink that involves melting the chocolate wih the almonds and milk, then chilling it in the refrigerator. Did the Aztecs really drink their chocolate cold often enough that it is the authentic way? Wikipedia indicates that it was served at all temperatures, so maybe I am being a purist, but I am thinking hot chocolate. Maybe it's the endless rain.
The final step in the process includes this: "...place in a blender or shaker..."
But, but, but... (she sputters)
What about a delightful carved wooden molinllo? Yes, I know this is totally inauthentic, being invented by the Europeans who came over and "found" a continent that was not lost, being full of lovely people as it was. But it's pretty well associated with chocolate from south of the US border over the few hundred years it's been around and they said a blender! A blender!