Step 1

For the Herb Butter: Place all ingredients in a food processor and process until smooth. Spoon onto a piece of plastic wrap and roll into a log shape. Chill until firm.

Step 2

Fill a pot or other large container half full of hot or warm water. Preheat sous vide immersion cooker to 130° Fahrenheit. Vacuum seal filet mignon in a plastic bag using a vacuum sealer or water displacement method (see Notes). Place bag in water bath.

Step 3

Cook at least 1 hour (for 1-inch thick filet mignon), and no more than 4 hours (for 2.5-inch thick filet mignon).

Step 4

Remove filet mignon from bag and pat very dry. Season with salt and pepper.

Step 5

Heat cast iron skillet over medium heat for 3 to 5 minutes. Add butter, then immediately add steaks. Cook 2 minutes, then flip and cook another 2 minutes. Make sure steaks are coated in butter on each side in order to caramelize the exterior.

Step 6

When browned on both sides, plate and top with herb butter.