The tenderloin roast, or Chateaubriand, is absolutely the most tender, melt-in-your-mouth roast beef available. It is extremely fine grained, and prized by top chefs for its buttery texture.
Tenderloin needs to be relatively well seasoned, with good browning, to bring out its flavour.
Sold as a 3-pound roast. Available in grass-fed or grain-finished beef.