For the Beef Tenderloin:

1. Preheat the oven to 400°F (200°C).
2. Butterfly the beef tenderloin by slicing it horizontally down the center, but not all the way through, so it opens like a book.
3. In a bowl, combine the lump crab meat, breadcrumbs, mayonnaise, Dijon mustard, chopped parsley, salt, and pepper.
4. Spread the crab mixture evenly over the inside of the butterflied beef tenderloin.
5. Carefully roll the tenderloin back into its original shape and tie securely with kitchen twine at intervals.
6. Season the outside of the tenderloin with salt and pepper.
7. Heat olive oil in an oven-safe skillet over medium-high heat. Sear the beef tenderloin on all sides until browned, about 2-3 minutes per side.
8. Transfer the skillet to the preheated oven and roast for 25-30 minutes, or until the internal temperature reaches 135°F (57°C) for medium-rare.
9. Remove the tenderloin from the oven and let it rest for 10 minutes before slicing.

For the Bearnaise Sauce:

1. In a small saucepan, whisk together the white wine vinegar and chopped tarragon over medium heat until reduced by half.
2. Remove the saucepan from heat and let it cool slightly.
3. In a blender or food processor, blend the egg yolks until frothy.
4. With the blender running, slowly pour in the melted butter in a steady stream until the mixture thickens.
5. Add the reduced vinegar and tarragon mixture to the blender and blend until smooth.
6. Season the Bearnaise sauce with salt and pepper to taste.

To Serve:

1. Remove the kitchen twine from the beef tenderloin and slice into thick rounds.
2. Arrange the slices on a serving platter and drizzle with Bearnaise sauce.
3. Garnish with additional chopped parsley, if desired.
4. Serve immediately and enjoy!