What do you mean by one step prior to the universe coming to be? Is that anything like one step prior to God coming to be?
So, rather than ask inane quesitons, please answer my question. Regress the cause back to the point just prior to the big bang. Take us one step back. You said you could infinitly regress everthing, so just take the one step prior to the big bang. I am interested in your answer. Please use scientific method and be consistent with naturalistic materialism which all evolutionists must be.