Melt 1 tablespoon butter in heavy medium saucepan over medium-high heat. Add shallots and sauté until beginning to brown, about 5 minutes. Add peppercorns and mash with back of fork. Add broth, Cognac, and cream and boil until sauce is thick enough to coat spoon, whisking occasionally, about 15 minutes. Set sauce aside.
Melt remaining 1 tablespoon butter with olive oil in heavy large skillet over medium-high heat. Sprinkle steak with salt and pepper. Add steak to skillet and sauté until brown and cooked to desired doneness, about 4 minutes per side for medium-rare. Transfer steak to cutting board. Add reserved sauce to same skillet and bring to boil, stirring to scrape up browned bits.
Slice steak thinly. Transfer steak to platter. Serve with sauce.