Porter Houses are the crème de la crème of T-Bones. The best T-Bone you can get (from a regular domestic cow that is). While it IS a NY Strip on the long side and a Club Steak (super hard to find) on the short side, BOTH are better when attached to the bone.
During grilling, the bone diffuse the heat making the meat right next to the bone as tender as any Filet Mignon, and the bone cooking and releasing a bit of the marrow only sweetens the meat.
You’ve got your hands on one of the best T-Bones there is. Enjoy.
As others said, cook it as usual. About 4-5 minutes per side for medium rare, rest, then chow down. You’re in for a treat. Especially at that price since Porter House is typically 3 or more dollars per pound above a regular T-Bone.
What kills me, if you shop right, you can find NY Strip for 9.99 or more a pound, but a T-Bone or Porter house for 5.99 or less. DUH!!!
Porter Houses are typically more marbled than a regular T-Bone, so you are sitting pretty!
Great job man!!