How to add structured data to a Squarespace blog post

Squarespace has not been keeping up with the http://schema.org/Article structured data specification in its generation of HTML for blog pages.  It is missing several properties that Google considers either required or essential.  This results in blog pages showing errors in the Google Webmaster Tools (Specifically the Structured Data Testing Tool).  In this post I show how I fixed this problem using the Squarespace Code block.