Mix cocoa, cinnamun and sugar.
Add 3 cups of milk and bring to a simmer. Stir frequently.
Beat egg yolks with 1 cup of milk.
Add corn starch to milk mixture and beat until the corn starch is fully incorporated.
Slowly pour milk/egg mixture into simmering milk/cocoa mixture, stirring constantly with a whisk.
Continue cooking and stirring until the mixture begins to bubble.
Remove from heat, add vanilla and orange oil and stir to incorporate.
Serve cold with whipped cream.
