Pat the steaks dry with paper towels, then season generously on both sides with kosher salt and ground black pepper. Allow the steaks to sit out at room temperature.
Place a skillet over medium heat, then add whole peppercorns. Toast, shaking the pan a little, then remove from the heat. Pour the peppercorns into a mortar. Use the pestle to coarsely grind.
Add neutral oil, then heat until smoking. Using tongs, carefully add the steaks and sear on their sides, fat strip side down. Flip the steaks, add the smashed garlic cloves, then cook. Transfer the steaks to a cutting board to rest, but leave the garlic in the pan.
Lower the heat to medium and add unsalted butter. To the garlic, add diced shallot. Cook, stirring often, until softened. Add Brandy, then use a spatula to scrape any browned bits off the bottom of the pan. Cook, then add heavy cream and coarsely ground black pepper.
Cut the rested steak into strips, transfer to serving plates, then spoon the peppercorn sauce on top. Sprinkle the steaks with flaky sea salt and chopped parsley. Enjoy!