Saving a completed mix on another track in the mix.

I would like to save a copy of my completed mix on my daw. That way I can use this as a reference to what I mixed and be able to make changes in the mix that I think I  need. I cant figure out how to add a stereo track and record the whole mix on the stereo track I just made. Any help would be appreciated.

I usually route the bounced track to direct outs rather than letting it go through the master bus again.