Remove steak from the refrigerator, salt both sides with kosher salt, then allow steak to come to room temperature prior to cooking for 30-60 minutes.
Coarsely crush whole peppercorns and after steak has the chill off of it, press the peppercorns into one side of each of the steaks. If you prefer, you may pepper both sides.
Heat cast iron or skillet of choice such as stainless over medium high heat. A skillet with a nice even heat distribution is ideal. Once the pan is heated, add the oil or ghee. It should shimmer when hot enough and just slightly begin to smoke.
If only peppering one side of the steak, start with the un-peppered side down first. Sear for 3-4 minutes each side or until internal temperature is approximately 125F or your preferred temperature. Use caution not to burn the pepper. Transfer to a warm plate, and cover while the sauce is made. Note, the internal temperature of the beef will increase upon resting a few degrees.
Add 1 tbsp butter to the pan and add shallots. Cook on low-medium heat until translucent. Add garlic and cook until fragrant being careful not to burn.Turn off heat momentarily. Add cognac, turn heat back on and simmer until reduced by half. Add heavy cream, stir and continue to cook until sauce is thickened nicely. Upon stirring it should coat the spoon nicely. Add ½ tsp of crushed pepper to sauce. Add thyme. Turn off heat and whisk in 2 tbsp butter. Serve immediately.
