Friends, lurkers, countrymen: I've said something like the following on other threads, so if it looks familiar, it's the 2003 edition.
Rip another Big Bang, you may not get exactly earth, but if the initial event is similar enough, if the rules of physics are the same, you get another nice even cloud of hydrogen, helium, and a little lithium. Get that, and you'll get stars.
Get stars, and you'll get iron. The rules for the iron atom, the same in all the stars all over the sky, weren't in the gas cloud at the start of the universe, or its size. They're in the laws of physics. The properties of the iron atom and of its neighbor atoms in the periodic table have everything to do with why stars that go supernova do what they do and when. Supernovas seed interstellar space with heavy elements. Doing this allows the formation of second- and third-generation solar systems rich in heavy elements. (Solar systems, in other words, that can look like our own.)
Already in our scenario what most human minds perceive as order and complexity have greatly increased in the universe over that almost-uniform gas cloud. How things could happen from there on a particular sunny planet living in the energy flow between its star and the dark beyond don't have to be any more magical than what we have described already. Here's one scenario, genuinely conjectural but not magical, out of many which still vie for consideration.