In a heavy bottom sauce pan add sugar, coco powder, corn starch and salt. Whisk to combine.
Add milk and continue to whisk until well combine. Transfer the pan to medium-low heat and continue whisking until mixture becomes thick and bubbles start to appear (about 1-2 minutes).
Remove from heat. Add butter and vanilla extract, then whisk until butter melts.
Pour the chocolate pudding into dessert cups and sprinkle some chocolate shaving on top.
Cover the cups with plastic wraps and chill in the fridge for at least 2 hours.