Melt 1 tablespoon of butter in a skillet over medium heat. Add the shallot and cook until softened, about 2 minutes. Stir in the peppercorns and cook for 30 seconds, until fragrant.

Remove the pan from heat, add the brandy, then return to the heat. Scrape up any brown bits and simmer for 1 minute until reduced by half. Pour in the beef broth and simmer for 2 to 3 minutes, until slightly reduced.

Lower the heat and stir in the heavy cream and Dijon mustard. Gently simmer for 2 to 3 minutes, until the sauce coats the back of a spoon. Off the heat, whisk in the remaining 1 tablespoon cold butter until glossy. Season with salt and spoon over rested steaks.