How to Make It
Heat 2 large skillets until very hot. Add 1 tablespoon of olive oil to each pan and swirl. Season the steaks with salt and pepper; add 3 to each skillet. Cook over moderately high heat, turning once or twice, for about 8 minutes total for medium-rare meat. Transfer the steaks to a large platter and keep warm.
Pour out all but 1 tablespoon of the fat from each skillet. Add half of the shallots to each skillet and cook over moderate heat, stirring, until slightly softened, about 2 minutes. Add half of the porcini to each skillet and cook, stirring occasionally, until golden, about 2 minutes. Add half of the brandy to each skillet and scrape up any browned bits stuck to the sides and bottoms of the pans. Add half of the stock and crème fraîche to each skillet and simmer until slightly thickened, about 1 minute.
Scrape the sauce from 1 skillet into the other and add any accumulated juices from the steaks. Stir in the chives and season with salt and pepper. Spoon the sauce over the steaks and serve.