In a medium saucepan over medium heat, whisk together the agave nectar, cocoa powder, heavy cream, and salt until the mixture comes to a simmer.
Remove from the heat.
In a separate bowl, whisk together the coffee and cornstarch.
While whisking constantly (especially if the coffee is still warm), add the egg yolks one at a time and then add the vanilla extract.
Return the pan containing the cocoa mixture to the stove.
Pour the egg mixture into the cocoa mixture, whisking constantly over medium heat.
Clip on a candy thermometer and whisk whisk whisk.
In all likelihood, the temperature has already exceeded 160 F (71 C), so you're safe, bacteria-wise.
Now keep whisking for about 5 minutes, until the pudding thickens and the temperature reaches 200 F to 210 F.
Pour the pudding into seven popsicle molds and freeze overnight for a luscious, chocolaty summertime treat.
You can also pour the pudding into fourteen individual 2-ounce serving cups and cover each with plastic wrap, making sure that the wrap touches the entire surface of the pudding to prevent a skin from forming, and refrigerate for a few hours.
You can serve the pudding straight from the fridge or with a dollop of whipped cream.
However, I like to sprinkle a spoonful or two of sugar over the top and take a kitchen torch to the sugar to caramelize it into a brulee crust.