Place your beef in the freezer for 10–15 minutes to firm it up slightly.
Using a sharp knife, finely chop the beef tenderloin by hand until evenly minced. Do not use a food processor.
In a chilled mixing bowl, combine Dijon mustard, shallots, capers, cornichons, parsley, and Worcestershire sauce.
Add the chopped beef to the mixture. Mix gently until well combined.
Season with salt and freshly cracked black pepper to taste.
Plate the mixture using a ring mold for clean presentation, and top with an egg yolk if desired.
Serve immediately with toast points, crostini, or fries.