Chop the chocolate roughly.
In a clean saucepan heat milk on medium flame.
Just as it comes to a simmer, turn off the flame and add the chocolate, coffee powder, vanilla extract, rum and orange zest (if using), allow the mix to stand for few minutes, until the chocolate melts and stir to a smooth sauce.
Once you have the sauce, turn on the flame and add the chocolate ice-cream.
Turn off the flame once the mix has warmed up a bit.
Pour the chocolate-coffee concoction in shot glasses and serve.
Chofee Shots are best enjoyed warm.