In a medium bowl, combine the softened butter, Dijon mustard, chopped parsley, Meyer lemon zest, salt, and pepper. Mix until well combined. Place the mixture onto a piece of parchment paper or plastic wrap. Roll it into a log shape and twist the ends to seal. Refrigerate until firm, about 30 minutes.

Remove the Porterhouse steak from the refrigerator and let it come to room temperature for about 30 minutes. Preheat your oven to 400°F (200°C).

Pat the steak dry with paper towels. Season generously with salt and freshly ground black pepper on both sides. Sprinkle the cracked caraway seeds and Meyer lemon zest evenly over the steak, pressing them into the meat.

In a large oven-safe skillet, heat the olive oil over medium-high heat until shimmering. Add the Porterhouse steak to the skillet and sear for about 4-5 minutes on each side until a golden-brown crust forms. Add the smashed garlic cloves and thyme sprigs to the pan during the last minute of searing.

Transfer the skillet to the preheated oven and roast for about 10-15 minutes for medium-rare, or until it reaches your desired doneness. Use a meat thermometer for accuracy (130°F/54°C for medium-rare).

Remove the skillet from the oven and transfer the steak to a cutting board. Let it rest for at least 10 minutes before slicing.

While the steak is resting, slice the compound butter into rounds. Serve the sliced Porterhouse steak topped with a dollop of mustard-parsley compound butter.