Sirloin with Bearnaise Sauce Recipe

Combine garlic salt and pepper; sprinkle over roast. Place on a rack in a shallow roasting pan. Bake, uncovered, at 325 ° for 2-1/2 to 3 hours or until meat reaches desired doneness (for medium-rare, a thermometer should read 145 °; medium, 160 °; well-done, 170 °). Let stand for 10-15 minutes before slicing. Meanwhile, in a saucepan, combine the vinegar, green onions, tarragon and pepper; bring to a boil. Strain, reserving liquid; discard green onions and tarragon. In top of a double boiler or a metal bowl over simmering water, whisk egg yolks, water and vinegar mixture until blended; cook until mixture is just thick enough to coat a metal spoon and temperature reaches 160 °, whisking constantly. Whisk in butter, 1 tablespoon at a time, until melted. Whisk in parsley. Keep warm. Cut roast into thin slices; serve with sauce.