Supernatural isn't a useful concept

[Ignorant]

Shouldn't time always be a correlate of any act, including the act of creation?

Not necessarily. Time is only a "correlate" of those acts which involve certain sorts of change. e.g. If something is pure act, that act is real despite the lacking of any change. Pure act, therefore, is "timeless". 

If creation involves the sorts of change which demand time (and it does), then time is a "correlate" of creation.

How did God create time outside of time?

If pure act creates, then "timeless" act brings about creation and its correlating time, "timelessly" (i.e. the pure act itself remains timeless while bringing about time-dependent creation).

How? How does god do any of the things he does? No answer to that question does not = the absurdity of the concept.