Pulse the semi-sweet chocolate chips in a food processor until chopped in to fine pieces. (Alternatively you can grate 4oz of your favorite chocolate bar or just add whole mini chocolate chips.)
In a mixing bowl, whisk together the powdered sugar, cocoa powder, dried milk powder and cornstarch,
Whisk in the chocolate chip pieces or grated chocolate.
Store in a large mason jar with a lid.
To make hot cocoa, use 2 heaped tablespoons of mix for every cup of hot liquid!