Turns out perfect every time, and by cooking it in a pan (rather than the bbq) you also get to make a nice pan sauce with the juices.
1 steak, 1 3/4" thick, room temperature, steak spice
1 Tablespoon oil, garlic flavoured is good
1 Tablespoon garlic butter
A small bit of onion or shallot if you like
Salt and pepper
Heat oven to 450 degrees
Over medium high heat, melt butter and oil together. When pan is hot, saute steak for 2 minutes on each side. Transfer frying pan to the oven to finish. No turning in the oven is necessary.
Steak - 6 minutes in the oven for rare, 8 for medium.
Remove from oven and immediately wrap tightly in tin foil for minimum 5 minutes.
Place the pan on the stove, and for steak, swirl in some butter - you can add a tiny bit of red wine or beef broth too - you are really just mixing up the cooking juices to pour over the steak.