"There are a lot of spice rub products on the market that promise to give a grilled steak that steakhouse crust, but I have never had any luck with them. I've found that the best way to mimic that steakhouse crust at home is to follow these steps."
1. While the steak is grilling, move your oven rack to the highest position and preheat your broiler and broiler pan to as high a temperature as it will go.
2. Remove the grill a few minutes before you think it is done. Spread a layer of (1 to 2 tablespoons) soft but not melted butter on the top of the steak.
3. Place the steak under the broiler for about 2 minutes or until the butter broils and almost burns.
4. Remove the steak, let it sit for about 1 minute, turn over, and butter and broil the other side of the steak. Remove from the oven, turn off the broiler, and let the steak rest for at least five minutes. Serve hot.
I only recommend this with a steak that is 1 1/2 to 2 inches thick; a thinner steak will end up overcooked. You can also broil only one side, just make sure you plate the steak with the broiled side up, so guests don't know you didn't do both sides!
NOTE: Use very good oven mitts, as the oven will be very hot. You have to broil the butter and remove the steak from the oven very fast to accomplish the crust without burning the steak."