Need to set 1500 MTU on PPPOE Client.

With a majority of ISP’s now silently supporting large ethernet frames in their infrastructure, I’d really like to know how to set a 1500 MTU to the PPPOE client. On 5.19 it seems to be a soft limit and forcing it to 1492.

and for those who want to know how this has occurred in the last 7 years:

https://tools.ietf.org/html/rfc4638