3 chateaubriand for with chateau potatoes and Recipes

beef tenderloin, trimmed, butter, salt, fresh ground black pepper, butter, white potatoes , cut tournee style, fresh parsley, finely chopped, white vinegar, white wine, peppercorns, shallots, finely chopped, tarragon, chopped, water, egg yolks, unsalted butter, melted, fresh parsley leaves, finely chopped

russet potato, peeled, butter, minced parsley, white wine vinegar, dry white wine, minced shallot, minced tarragon, black peppercorns, cracked, egg yolks, fresh lemon juice, melted butter, minced chervil, center-cut beef tenderloin , side muscle removed (prime or choice grade), olive oil, garlic cloves, mashed to a paste, frozen lobster tails, about 8 oz each, thawed, butter, softened, garlic cloves, mashed to a paste