Prepare the Steaks: Remove the Porterhouse steaks from the refrigerator and let them sit at room temperature for about 30 minutes. This will help them cook evenly.

Make the Rub: In a small bowl, combine the smoked sea salt and chopped fresh rosemary. Rub the mixture generously over both sides of the steaks. Drizzle the olive oil on top of the steaks and massage it into the meat.

Preheat the Grill or Oven: If using a grill, preheat it to high heat. If using an oven, preheat it to 450°F (230°C).

Grill the Steaks: Place the steaks on the grill and sear for about 4-5 minutes on each side for medium-rare, or until they reach your desired doneness. Use a meat thermometer to check for an internal temperature of 130°F (54°C) for medium-rare.

Rest the Steaks: Once cooked to your preference, remove the steaks from the grill and let them rest on a cutting board, tented with aluminum foil for about 10 minutes.

Prepare the Jus: In a saucepan, melt the unsalted butter over medium heat. Add the diced shallots and sauté until softened, about 3-4 minutes. Add the red currants and cook for another 2 minutes until they burst slightly.

Add Stock and Vinegar: Pour in the beef stock and balsamic vinegar. Bring the mixture to a simmer and let it reduce by half, about 5-7 minutes. Season with freshly ground black pepper to taste.

Serve: Slice the rested Porterhouse steaks and serve with the red currant and shallot jus drizzled over the top.