Add the butter to a small saucepan preheated over medium heat.

Add the minced shallot, and saute until soft, about 5 minutes.

Set aside to cool entirely.

Once cooled, mix the crab meat, parmesan cheese, mayo, old pay, panko sauted shallot in a large bowl. Season with a pinch of salt and pepper to taste.

Remove the beef tenderloin from the package.

Using a sharp fillet knife, butterfly the fillet.

Start by inserting the tip of the knife about ½” above the bottom of the roast and make long smooth slices, almost through to the other side. Leaving about ½” unsliced.

Fold open the meat, like a book, and repeat the process one more time, arranging your tenderloin into one ½” thin large flat surface.

Spoon the crab filling into the center of the tenderloin and press it into an even layer, about ¼” thick over the tenderloin, leaving 1” of beef exposed on one end.

Tightly roll the beef up, forming a tight log, starting from the end you exposed while butterflying it. You will have filling left over.

Securely tie the stuffed tenderloin every 1 ½” with butcher's twine to hold it together and maintain its shape.

Line a large baking sheet with foil and arrange a wire rack over top.

Place the tenderloin on the rack and let it sit at room temp for 45 minutes.

Roast the tenderloin for 30 to 45 minutes until the internal temp reaches 125 degrees F.

Be careful when inserting the probe of the thermometer to make sure it’s inserted in beef for the most accurate results.

Remove the roast from the oven.

Preheat a large cast iron skillet over medium-high heat until just smoking.

Add 4 tbsp butter to melt.

Using long tongs, add the tenderloin and quickly sear on all sides, just for color and texture, about 3 minutes per side.

Transfer the roast to a cutting board and tent it with foil.

Let the roast rest for 10 minutes before slicing into ½” thick slices.

Serve immediately.