Well, in chapter one, it seems to be a simultaneous creation.
And yeah, God could have done it all at once, but where's the fun in that? ^_^
Listen carefully to the answer:
Qura'an Ch.21
16 We created not the heaven and the earth and all that is between them
in play.
17 If We had wished to find a pastime, We could have found it in Our presence - if We ever did.
18 Nay, but We hurl the true against the false, and it doth break its head and lo! it vanisheth. And yours will be woe for that which ye ascribe (unto Him).
19 Unto Him belongeth whosoever is in the heavens and the earth. And those who dwell in His presence are not too proud to worship Him, nor do they weary;
20 They glorify (Him) night and day; they flag not.
21 Or have they chosen gods from the earth who raise the dead ?
22 If there were therein gods beside Allah, then verily both (the heavens and the earth) had been disordered. Glorified be Allah, the Lord of the Throne, from all that they ascribe (unto Him).
23 He will not be questioned as to that which He doeth, but they will be questioned.
24 Or have they chosen other gods beside Him ? say: Bring your proof (of their godhead). This is the Reminder of those with me and those before me, but most of them know not the Truth and so they are averse.
25 And We sent no messenger before thee but We inspired him, (saying): There is no God save Me (Allah), so worship Me.
26 And they say: The Beneficent hath taken unto Himself a son. Be He Glorified! Nay, but (those whom they call sons) are honoured slaves;
27 They speak not until He hath spoken, and they act by His command.
28 He knoweth what is before them and what is behind them, and they cannot intercede except for him whom He accepteth, and they quake for awe of Him.
29 And one of them who should say: Lo! I am a god beside Him, that one We should repay with hell. Thus We Repay wrong-doers.
30 Have not those who disbelieve known that the heavens and the earth were of one piece, then We parted them, and we made every living thing of water ? Will they not then believe ?
Big bang!