Stuffed Beef Tenderloin

Still catching up on drafts from the past.  Made this recipe with mom during week before Thanksgiving (2019), was very delicious, but forgot to note what rating out of 10 (am guessing it was a 10 :))  We only used 2 packages of spinach and that was plenty (original recipe calls for 3).

Link to original recipe: https://www.myrecipes.com/recipe/stuffed-beef-tenderloin-with-burgundy-mushroom-sauce

Ingredients: 

for the beef-- 2 (10-oz.) pkg. frozen chopped spinach, thawed
3 T. unsalted butter
2 medium leeks, thinly sliced
1 garlic cloved, minced
3 T. all-purpose flour
1 c. heavy cream
1 oz. Parmesan-Reggiano, grated
2 tsp. fresh lemon juice
1/4 tsp. grated whole nutmeg
2 tsp. kosher salt, divided
1 tsp. black pepper, divided
4 lb beef tenderloin section, trimmed

for the sauce--
2 T. unsalted butter, divided
1 T. olive oil
16 oz. cremini mushrooms, quartered
1 medium shallot, minced
1/2 c. dry red wine
1 c. beef broth
1 T. Dijon mustard (I think we used Grey Poupon-style one)
1/2 tsp. fresh rosemary
1/2 tsp. kosher salt
1/4 tsp. black pepper

Directions:

1. Drain spinach well, pressing between paper towels to remove excess moisture.

2. In a medium saucepan over medium heat, melt the butter.  Add leeks and garlic and cook, stirring occasionally, until softened (around 3-4 min).

3. Sprinkle flour atop the mixture and stir, cooking for another 3 min.

4. Whisk in cream until smooth. Stir in spinach and cook, stirring occasionally, until mixture is thickened (around 5 min.)

5. Add cheese, lemon juice, nutmeg, 1 tsp. of the salt, and 1/2 tsp. of the pepper, stirring to combine.  Remove from heat and let mixture cool for 10 min.  Heat oven to 350°F.

6. Meanwhile, butterfly the beef and open it like a book, spreading flat.  Place between 2 sheets of plastic wrap and pound to 1/2" thickness all over using a meat mallet, making around a 13" square (we had to piece the meat together a little to do this).

7. Remove plastic wrap and spread the cooled mixture evenly over the beef, leaving a 1/2" border around edges.  Roll up beef and tie with kitchen twine.

8. Brush all over with olive oil, then sprinkle with remaining salt and pepper.  Place beef on a wire rack set over a rimmed baking pan.  Transfer to oven and bake for 30 min.

9. Increase heat to 450°F and bake for additional 20 min, or until meat thermometer registers 125°F inserted in center.  Let stand 30 min. before slicing.

10. While beef rests, prepare the sauce.  In a large skillet over medium-high heat, melt 1 T. of the butter together in skillet with olive oil (swirl to combine), then add mushrooms.  Cook, stirring a couple of times, until lightly browned (around 5-6 min.)

11. Add shallot and cook, stirring constantly, 1-2 min.  Carefully add wine to skillet and stir in, cooking 2 additional minutes.

12. Stir in broth and reduce heat to medium.  Let simmer for 5 minutes.

13. Mix in the mustard, rosemary, salt, and pepper.  Cook for 1 minute.  Remove from heat and stir in the remaining 1 T. butter until combined.  Serve sauce with beef and enjoy!