What did God make the universe from? What did God make the universe from? It seems Himself, since before Creation, only God is.

This seems to me to be the most important question for Christianity. NOT why, how, where or who, but what. From what outside or within Himself, could God have made the universe?
As science suggests, the physical universe of time, space, and matter is not eternal.  It had a beginning.  Thus it was created.  It was not arranged or mixed or reassembled, but created out of nothing.  

Genesis 1 repeatedly uses the phrase, "God said, 'Let there be...', and there was...".  God spoke, and what previously did not exist began to exist.  So, specifically, God did not make the universe from anything at all.

Indeed, God did not make the physical universe from Himself, because He Himself is outside the physical universe.  In fact, God is spirit.  This is in contrast to the idea of pantheism.  

In the 11th chapter of Hebrews, we read this:


  By faith we understand that the universe was formed at God’s command,
  so that what is seen was not made out of what was visible.


This ex nihilo power is reserved to God alone.  All other creations that mankind does is simply to take what is already made and rearrange it into another form.  We never really "make a cake"--we merely assemble ingredients into a different form.