Liberally season steak with salt and pepper, being sure to coat the entire surface of the meat.
Sear steak over 450 degree direct heat on the cast iron grid to desired doneness. Transfer steaks to a platter to rest.
Heat a skillet to medium high heat. Add brandy to cook down for 1 minute. When brandy has reduced by half, add the cream. Whisk to combine. Add the dijon mustard and butter. Cook until mixture begins to reduce and thicken.
Slice the steak into 1/2 inch pieces. Pour cream sauce over the strips and serve.