Prepare the Steak: Season the steak and cook sous-vide at 130°F for an hour and a half.
Make Bearnaise Sauce: Combine vinegar, wine, shallots, peppercorns, and lemon peel; reduce by half. Emulsify with egg yolks and melted butter, then add herbs and mushroom powder.
Sear the Steak: Remove steak from sous-vide, dry well, and sear in a hot pan with olive oil.
Rest and Serve: Let the steak rest, then serve with Bearnaise sauce.