Serve this butter alongside the Seared Porterhouse Steak.
Stir together all ingredients in a medium bowl with a flexible spatula until well combined.
Place butter mixture on the center of a sheet of parchment paper, then loosely fold paper in half toward you and roll back and forth to form butter into a log. Then, while pulling parchment taut, push with a straightedge (such as the rim of a baking sheet) to mold into a neat cylinder, pressing hard to remove any air pockets. Wrap parchment around butter, then twist end to seal and tie with twine.
Refrigerate until firm, about an hour.