- 2 Tablespoons Dijon mustard
- 2 Tablespoons coarse (kosher) salt
- 1 Tablespoon freshly cracked black pepper
- 6 garlic cloves, 4 cloves left whole, 2 finely minced
- 1 center-cut, trimmed section of beef tenderloin (trimmed before weighing), 2 pounds
- 2 loosely packed cups flat-leaf parsley leaves
- 1/2 to 3/4 Cup extra virgin olive oil
- 1 Tablespoon white wine vinegar or fresh lemon juice
Mix mustard, salt, pepper and 2 cloves minced garlic in a small bowl. (Refrigerate covered up to 1 day; use at room temperature.)
Heat oven to 425 degrees.
Place beef on a rack set in a shallow roasting pan.
Spread mustard mixture over all surfaces of the beef tenderloin.
Roast uncovered until an instant-read thermometer inserted in the thickest part of the meat registers 130 degrees for medium-rare, 30 to 35 minutes, or 140 degrees for medium doneness, 40 to 45 minutes.
Remove roast from oven; transfer to a carving board and cover loosely with aluminum foil.
Let stand, 10 to 15 minutes; temperature will rise a few degrees.
Meanwhile, pulse 4 remaining whole garlic cloves in a blender or food processor until finely chopped.
Add parsley and chop with on/off turns.
With the machine running, slowly drizzle in the oil and vinegar.
Transfer to a small serving bowl.
Season with salt.
To serve, slice the tenderloin into 1/4-inch thick slices.
Arrange on a warm platter.
Be sure to pour any juices over the slices.
Drizzle slices with a bit of the parsley sauce.