SOLVED: How Can I SHADOW a Remote Desktop / Terminal Services User in Server 2012

This is a short answer, upgrade to Server 2012 R2.  In Windows Server 2012, Shadowing was removed but it is back in Windows Server 2012 R2:

OPTION 1:

1. run MSTC / SHADOW

OPTION 2:

1. Open SERVER MANAGER
2. Click REMOTE DESKTOP SERVICS
3. Click COLLECTIONS (left pane)
4. Under CONNECTIONS (bottom right) right click on the connection you want to SHADOW and select… wait for it… SHADOW

OPTION 3:

1. Determine the target users SESSION ID from CONNECTIONS section (see step 4 above)
2. run MSTC.exe /shadow:sessionID /control /noConsentPrompt