I have recently cooked the perfect fillet steak.
First i recomend buying the best fillet you can, 21 day matured steak or older is great. next a hot dry pan and seal your meat very quickly on all sides using tongs, then remove from the pan, now this next bit will throw alot of people but trust me it is worth it, place your fillet on some cling film and roll it up in about 20 layers, twist the ends so the parcel is tight and has no air in with the steak, secure the loose ends by folding over and one more wrap of cling film to secure. Next place your bundle in the oven for an hour at 65-70 degrees C,yes that low, you may need a seperate thermometer, After your hour is up remove from the oven, remove the cling film and return the fillet to the pan to colour it, rest for 5 minutes and serve.
The steak will look very pink but dont let this put you off, close your eyes and enjoy, its better than any i have eaten anywhere.