Excellent low glycemic hot chocolate mix: cocoa powder, coconut palm sugar, cinnamon.
For a typical glass mix in 1:1:1 ratio 1 tablespoon of cocoa powder, 1 tablespoon of coconut palm sugar, 1 tablespoon of cinnamon with warmed up high fat milk. If you're not a wimp, add some high fat cream to the mix.
1:1:1 is a starting point. If you like more chocolaty/bitter taste, add more cocoa powder. If you like more sweet, add more coconut palm sugar. If you like more cinnamony/spicy taste, add more cinnamon. Cinnamon (the good stuff, not the so-called 'sweet cinnamon' which I think is sand) adds to sweetness as well, so you can probably reduce the amount of sugar.
Stir often as the cinnamon will tend to sink to the bottom.
As far as brands I use: Camino Cocoa Powder (either natural or Dutch-processed), Organic Traditions coconut palm sugar and Simply Organic cinnamon.