Two easy steps: Jetstar from Darwin to Singapore, Finnair from Singapore to Helsinki. Of course, this might not be the fastest route for you, unless you already happen to be in the Top End. I was, which meant I was in the passport control queue at Helsinki Airport in less than 19 hours after wheels off at Darwin.
I was flying on a OneWorld ticket, and as Qantas is code sharing on the Jetstar flight, I was actually served a hot meal! I also got a beauty bag full of useless goodies, such as single-use socks that will have covered your feet in ugly black fluff by the time you take them off; to be fair, the ear plugs might come in handy one day. This was notable mainly because neither Finnair nor, I think, Qantas actually hand out stuff like ear plugs and eye shades (and certainly not inflatable travel cushions) any longer.