Why did my attempt at pan-searing beef filets fail miserably? Background: I am very much an amateur cook; I would consider myself a novice at best, so pardon my ignorance!

I decided to try to cook a nice dinner for my family recently. Part of that dinner included some small (~6-7 oz., 1.5-2" thick) beef tenderloin steaks. After doing some Internet research I decided on a preparation method that included pan-searing them for a few minutes on each side (with the goal of getting the steaks to the approximately "rare" stage), followed by a stint in the oven to finish them off. This seemed straightforward to me, so I decided to give it a try.

As a novice cook, the only skillet that I had on hand that was suitable for use in the oven was an old cast-iron one, so I used that. Following the recipe that I had found, I added 1.5 tablespoons of olive oil and ~1 stick of butter [*] to the pan and put it on high heat. After the foam subsided from the butter, I placed the steaks in the pan. The Internet consensus seemed to indicate 3-4 minutes of searing on each side would get the steaks to rare, so I waited patiently.

Unfortunately, after 3 to 3.5 minutes, it became apparent that something had gone wrong: the kitchen began to fill with smoke, and when I turned the steaks, the side that had been seared was burned horribly. I had to abort cooking them at that point to mitigate the smoke; I later found that the steaks had cooked through much more than I would have expected by that point.

While my result was discouraging, I'm trying to do some post-mortem analysis to try to determine what went wrong so that if I get up the nerve to try this again, I won't ruin another meal of expensive meat! Some possibilities that came to mind:


Was cast iron a bad choice as my cookware in this case?
Should I have lubricated the pan differently?
Is there some other detail that I missed that could have changed the outcome?


[*] "A stick of butter" is a US measurement, it denotes 113.5 g of butter
Butter is a very bad choice for frying at high heat, as it burns extremely easily. Cast iron is the ideal pan material though, so you are halfway there. 


Take a flavourless oil like sunflower and brush it
directly on the steaks - don't put the oil in the pan. 
Preheat the pan until it is ridiculously hot.
Preheat the oven if that's the
method you're going to use
Season the steaks generously with salt and
pepper
Sear the steaks and cook in the oven until desired level of
doneness is reached.
Rest the steak on a wire rack (or failing that, a plate) for 5 minutes so it doesn't leak juice all over the plate.


Personally I would omit the oven stage and just cook the steaks in the pan, turning frequently. Add a knob of butter near the end and baste it over the steaks with a spoon.

A probe thermometer is a great investment to make if you plan on cooking meat properly. You cannot rely on rules of thumb like pressing the steak or just timing it. There is a good chart here for the temperatures at each level of 'doneness'.