Remove the Iberian pork secreto from the refrigerator 15–20 minutes before cooking and pat it dry with paper towels.
Season both sides generously with kosher salt (or flaky sea salt) and freshly ground black pepper.
Heat a heavy skillet or grill pan over high heat until it just starts to smoke. Optionally, rub the pan with the cut side of the garlic clove before adding 1 tablespoon of extra-virgin olive oil for extra flavor.
Place the pork in the pan and cook for 3–4 minutes per side, until browned on the outside and an instant-read thermometer inserted into the thickest part reads 145°F (63°C).
Transfer the pork to a cutting board, loosely tent with foil, and let it rest for 5 minutes.
Slice into 1/2-inch-thick slices, sprinkle with additional flaky salt if desired, and serve.