This easter egg has been right in front of us the whole time! The Locomotive hat, which is part of the "Revenge of the Battle-Cars DLC Pack", contains a cart with a loaf of bread. It can be seen clearly in the image below.

This is, of course, a reference to Dave Hagewood's comment on a Twitch stream, which is now known as BreadGate. The easter egg could also have been a hint, that Psyonix has not forgotten about the bread.

Psyonix announced October 22nd, 2015 that Dave will be eating bread on the 29th of October, live on Twitch. This was posted on the official Rocket League Twitter.

#BreadGate will finally be over with soon!