Make a simple syrup by combining sugar and water in a small saucepan over medium heat. Heat until sugar dissolves completely and mixture comes to a simmer. Whisk to fully blend. Remove from heat.
Whisk in the sifted cocoa, salt and vanilla. Blend thoroughly.
Strain to remove any lumps and add the milk or cream. Transfer bowl to freezer to chill completely, whisking every 20 minutes so it doesn’t ice up.
Whisk a final time and fill the ice cream pop moulds and follow directions for freezing and removing moulds. Best when frozen overnight.