How to record stereo output in Logic Pro X

I am trying to record the stereo output in Logic Pro X on the spare stereo track. In other words what I would like to do is to record audio/software instruments tracks existing in my project as well as my real time performance on top of that (let's say a software synth played using a midi controller) to a new stereo track, just like if I were recording Logic's stereo out to an external recorder except in this case you are recording that to a spare tracks within Logic X.

Any help will be highly appreciated.