Spinach and Mushroom-Stuffed Beef Tenderloin with Truffled Wine Sauce

Ingredients

• 3 slices applewood-smoked bacon finely chopped
• 6 ounce baby spinach coarsely chopped
• 3 cups beef stock unsalted divided (such as Swanson)
• 3.3 pound beef tenderloin trimmed
• 1 teaspoon pepper black divided freshly ground
• 3 tablespoons butter 
• 16 ounce cremini mushrooms finely chopped
• 5 teaspoons flour all-purpose
• 1 tablespoon garlic minced
• 2.5 tablespoons olive oil divided
• 1 cup red wine (such as pinot noir)
• 1.5 teaspoons salt divided
• 0.5 cup shallots finely chopped
• 3  thyme sprigs 
• 2 teaspoons truffle oil 

Equipment

• bowl
• frying pan
• oven
• knife
• whisk
• plastic wrap
• kitchen thermometer
• meat tenderizer
• kitchen twine

Directions

1. Heat a large skillet over medium heat.
2. Add 1 tablespoon olive oil to pan; swirl to coat.
3. Add bacon; cook for 2 minutes, stirring occasionally.
4. Add shallots; cook 2 minutes, stirring occasionally.
5. Add mushrooms; cook 3 minutes, stirring occasionally. Increase heat to medium-high.
6. Add garlic; saut 30 seconds. Stir in 1/2 cup beef stock; cook until liquid almost evaporates, stirring occasionally (about 8 minutes).
7. Add spinach; cook 1 minute or until spinach wilts.
8. Preheat oven to 35
9. Cut horizontally through center of beef, cutting to, but not through, other side using a sharp knife; open flat, as you would a book.
10. Place beef between 2 sheets of plastic wrap; pound to an even 1/2-inch thickness (about 13 inches square) using a meat mallet or small heavy skillet.
11. Brush beef with 1 1/2 teaspoons olive oil; sprinkle with 3/4 teaspoon salt and 1/2 teaspoon pepper.
12. Spread mushroom mixture evenly over beef, leaving a 1/2-inch border around edges.
13. Roll up beef, jelly-roll fashion. Secure at 2-inch intervals with twine.
14. Brush all sides of beef evenly with remaining 1 tablespoon olive oil; sprinkle with 1/2 teaspoon salt and 1/4 teaspoon pepper.
15. Place beef on a jelly-roll pan.
16. Bake at 350 for 30 minutes. Increase oven temperature to 450 (do not remove beef from oven); bake an additional 25 minutes or until a thermometer registers 12
17. Let stand 15 minutes; cut across the grain into 12 slices.
18. Combine remaining 2 1/2 cups beef stock, wine, and thyme, and bring to a boil. Cook until reduced to 1 cup (about 25 minutes). Discard thyme sprigs.
19. Combine 1/4 cup stock mixture and flour in a small bowl, stirring with a whisk until smooth.
20. Add flour mixture to stock mixture. Bring to a boil; cook 1 minute, stirring occasionally.
21. Remove from heat, and stir in remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, butter, and truffle oil.
22. Serve sauce with beef.