6 Servings 35 min Cook
1 1/2 Tsp Pepper
1 1/2 Tsp Salt
4 Lb Porterhouse Steak
1/4 Cup Horseradish
1 Cup Sour Cream
4 Medium (4-1/8" long) Scallions
Finely chop scallions.
Prepare grill for cooking over direct heat with medium-hot charcoal (moderate heat for gas).
While coals are lighting, let steaks stand at room temperature about 15 minutes.
Stir together sour cream, horseradish, scallions, 1/2 teaspoon salt, and 1/2 teaspoon pepper in a bowl.
Pat steaks dry and sprinkle all over with remaining teaspoon each of salt and pepper.
Grill steaks on lightly oiled grill rack, covered only if using a gas grill, turning steaks over once and moving them around grill to avoid flare-ups if necessary, until thermometer inserted horizontally 2 inches into meat (do not touch bone) registers about 120F for rare, 9 to 12 minutes total.
Transfer steaks to a cutting board and let stand 10 minutes before slicing.
(Internal temperature will rise to 125 to 128F while steaks stand.
) Thinly slice meat and serve with sauce.