Slow Roasted Whole Beef Tenderloin

Slow-Roasted Filet of Beef with Basil Parmesan Mayonnaise 

Many thanks to the Barefoot Contessa for this recipe.  It really is a foolproof recipe using basic ingredients and simple techniques.  Ina exemplifies these methods in many of her recipes. Enjoy!

To simplify further make the Basil Mayo in advance. 

Takes about 2 hours.

Serves 6-8. 

Ingredients

• 1 whole filet of beef tenderloin, trimmed and tied (4 - 4½ pounds)

• 3 tablespoons good olive oil

• 4 teaspoons kosher salt

• 2 teaspoons coarsely ground black pepper

• 10 to 15 branches fresh tarragon (or your favorite dry rub)

• Basil Parmesan Mayonnaise, for serving (recipe follows) 

• Internal Thermometer

Preparation

1. Preheat the oven to 275 degrees. Definitely use an oven thermometer to be sure your oven temperature is accurate. Additionally a meat thermometer will keep you from potentially ruining an expensive cut of meat. Insert meat thermometer sideways into the center of the tenderloin. Alternatively this can also be done on a gas grill by lighting the two outside burners and finding the right spot to cook with indirect heat.

2. Place the filet on a sheet pan and pat it dry (all over) with paper towels. Brush the filet all over with the oil, reserving about half a tablespoon. Sprinkle it all over with the salt and pepper (it will seem like a lot but believe me, it makes a difference). Place the tarragon branches around the beef, tying them in 4 or 5 places with kitchen twine to keep them in place, and then brush the tarragon with the reserved oil.

3. Roast the filet of beef for 1¼ to 1½ hours, until the temperature registers 125 degrees in the center for rare and 135 degrees for medium-rare. Using a meat thermometer and cooking slowly like this ensures a consistent cook all the way thru. We removed ours at 130 degrees then covered the filet with aluminum foil and allow to rest for 20 minutes. This delicacy could be sliced thick or thin then served warm with the Basil Parmesan Mayonnaise.

Side dishes might be Sautéed Mushrooms and Melting Potatoes along with a side salad.

Basil Parmesan Mayonnaise

• 2 extra-large egg yolks, at room temperature

• 3 tablespoons freshly squeezed lemon juice

• ½ cup freshly grated Parmesan cheese

• 1 tablespoon Dijon mustard

• ½ cup chopped fresh basil leaves, lightly packed

• ½ teaspoon minced garlic

• Kosher salt and freshly ground black pepper

• 1 cup vegetable oil, at room temperature

• ½ cup good olive oil, at room temperature

Place the egg yolks, lemon juice, Parmesan, mustard, basil, garlic, 1 tablespoon salt, and 1 teaspoon pepper in a food processor fitted with the steel blade. Process for 20 seconds, until smooth. Combine the vegetable oil and olive oil in a 2-cup liquid measuring cup. With the processor running, slowly pour the oil mixture through the feed tube to make a thick emulsion. Taste for seasonings – the mayonnaise is a sauce so it should be highly seasoned. Store in the refrigerator until ready to use; it will keep for up to a week. 

Recipe by Ina Garten the Barefoot Contessa 

Urban Cowgill 2014 (updated 2024)