Put peppercorns in a small resalable plastic bag and hit with a rolling pin until coarsely crushed. Pat the steaks dry with paper towels and season well salt. Dip 1 side of each steak into the peppercorns and press to help adhere.
Heat the butter and oil in a 10-inch heavy-bottomed frying pan over medium-heat until just smoking.
Add the steaks, peppercorn side up to the hot pan and cook, undisturbed, about 3 to 4 minutes. Flip and cook, pressing the steaks down in the pan so that the peppercorns adhere, about 4 to 5 minutes for medium-rare. Remove to a cutting board, tent with foil, and let rest at least 5 minutes.
Meanwhile discard all but 1 tablespoon of the drippings, return the pan to the stove over medium heat, add the shallots and cook until softened, about 1 minute. Stir in the beef broth and brandy. Scrape the bottom of the pan to incorporate any browned bits and cook until slightly thickened, about 4 to 5 minutes.
Add the cream and any accumulated meat juices and simmer until the sauce coats the back of a spoon, about 2 minutes. Stir in vinegar and season, to taste, with salt. Transfer the steaks to serving plates and drizzle with the sauce.