Begin by patting your ribeye or New York strip steaks dry with paper towels. Generously season both sides with kosher salt and freshly cracked black pepper, letting the steaks rest at room temperature for 30–45 minutes.

Heat a cast iron skillet over high heat until it starts to lightly smoke. Add a splash of neutral oil to the pan, then carefully lay the steaks in without overcrowding. Sear each steak undisturbed for 2–3 minutes on each side.

Once the crust is established, reduce the heat to medium and add 2 tablespoons of unsalted butter, along with the smashed garlic and fresh thyme sprigs. Baste the steaks continuously with the melted butter for 1–2 minutes.

Use a meat thermometer to check for an internal temperature of 130°F (54°C) for medium-rare. Let the steaks rest for 5–10 minutes before slicing.

Discard excess fat from the skillet, leaving about 1 tablespoon. Deglaze the pan with cognac, stirring in Dijon mustard and crushed black peppercorns, followed by heavy cream, allowing the sauce to simmer until thickened.

Slice the rested steaks against the grain into ½-inch thick slices. Plate the steak, spoon the Cognac cream sauce over, and garnish with fresh thyme and cracked pepper.