Sous Vide: Beef Tenderloin with Lemon-Parsley Butter

Ingredients

• One 1 1/2-pound center cut beef tenderloin, trimmed of all silverskin
• Kosher salt and freshly cracked black pepper
• 4 sprigs thyme
• 7 tablepsoons unsalted butter, softened
• 2 tablespoons chopped fresh parsley leaves
• 1 garlic clove, minced or grated on a microplane
• 1 teaspoon juice and 1 teaspoon zest from 1 lemon
• 1 tablespoons vegetable oil

Directions

1. With a sharp chef's knife or slicing knife, divide the tenderloin into four equal 6-ounce pieces. Set each piece on the cutting board with the cut side facing down, then press lightly with your palm until it is about two-inch thick. Sprinkle well with salt and pepper. Tuck the steaks into a vacuum bag with the thyme, seal it, and lower it into a water oven set at 130 degrees F for medium rare or 140 degrees F for medium. Cook the steaks for no less than 45 minutes and no more than 4 hours.
2. While the beef cooks, put 6 tablespoons of butter in a small bowl with the parsley, garlic, lemon juice, and lemon zest. Mash and stir with a fork until the mixture is smooth and evenly combined, then add salt and pepper to taste.
3. When you are ready to finish the steaks, take them out of the bag and blot them thoroughly with paper towels. In a heavy-bottomed 12-inch skillet set over high heat, heat the oil with the remaining butter until the butter turns brown and just starts to smoke. Lay in the steaks and sear until the first side is deeply browned, about 1 minute. Turn them over and brown the other side, about 1-minute longer. Move the steaks to a paper towel-lined plate, cover them loosely with foil, and rest them for at least 1 minute and up to 5 minutes. Spoon a dollop of parsley butter over each steak and serve.