Temper the egg(whisk the entire cooking time), use on a stove top, omit the sugar if using chocolate chips, and add a dash of cayanne if you're feeling adventurous. I also kept the cinnamon, but used just a little less then called for. I just sent my husband off to work 20 minutes ago with a big smile on his face! Next time i might add a packet of starchucks instant coffee to it as well. Keeper!
This made very nice hot cocoa. A tip with the egg so it won't make chunks: wisk the egg well in a small bowl so that it is an even color yellow, when the chocolate is all melted in the milk spoon 1 tablespoon of hot chocolate milk into the egg in the small bowl and mix well.
Do this 2 more times, then add the egg slowly into the milk and mix it in right away until the milk is frothy. The trick is to make the egg just warm enough that when you put it into the chocolate milk it doesn't cook as you add it.