Restoring a site collection with an External Data column

On a SharePoint on-premise environment, 

What is the correct process when restoring a site with an External Data column into another SharePoint farm or site collection?  

Typically, the BDC object gets broken in the custom list that references an External Data when I perform a backup/restore via PowerShell. I'm able to re-create the External List within SharePoint Designer but I would think that it will already be a different object at that point? Is it even possible to export or re-import them from production into a test farm? 

Fred Y