How to verify GPO is linked to all OU's

PowerShell Gurus,

I need to verify that the Default Domain Policy GPO is linked toall the OU's in my domain.

How can I generate a list of OU's where the Default Domain Policy is NOTlinked?

I'm close, but I'm missing something...

Get-ADOrganizationalUnit -Filter * | Get-GPInheritance  ???

I'm guessing I somehow need to filter on the $_.GPOLinks, or $_.InheritedGpoLinks properties?

Thanks in advance!

"T"