According to scientists, space-time was created along with the universe. It didn't exist before the Big Bang. So whatever generated the Singularity, is beyond space-time. It could be someone or something from a parallel universe, a set of engineers producing a simulation, a multiverse...whatever.
They are all beyond space-time (and the laws of physics) as we know it in this universe.
Unfortunately, as torridon suggests, the 'outside of space-time' cannot really be grasped meaningfully at all. You yourself are suggesting that space-time was created, which immediately suggests a time element, as does your use of 'generated', and 'didn't exist before the Big Bang'.
And, even if one tacitly accepts that someone/something from a parallel universe(outside of space-time) generated(generates?) the Singularity, then you are still left with the problem of who created(creates) this non space-time parallel universe, presumably out of some other non space-time state. And so on, ad infinitum.