Pork Tenderloin with Pan Sauce

"I found this recipe on Pinterest and it came from Chef Mommy who got it from For the Love of Cooking.  This was a great dish!  The sauce was awesome and may have been even better with a little brown sugar or honey, but fine on it's own.  I follow the ingredient list exactly, not adding anything, but I did make the sauce ahead of time, right after searing the meat and used all of the marinade, which I wished I would have followed the recipe (although it doesn't tell you to throw all but the reserved marinade in the pan when you sear it, but I think you're suppose to).  I will try that next time."

Ingredients:

1⁄2 cups olive oil
1⁄3 cup soy sauce
1⁄4 cup red wine vinegar
Juice of 1 lemon
1-2 tbsp Worcestershire sauce
1-2 tbsp fresh parsley, finely chopped
2 tsp dry mustard
Freshly cracked black pepper, to taste
4 cloves garlic, peeled and minced
1 1-lb. pork tenderloin (silver skin removed) (I used pork loin roast instead)

Directions:

Combine all marinade ingredients and reserve 2-3 Tbsp. Place the pork tenderloin and marinade in a Ziplock bag and let marinate for at least 3-4 hours.
Preheat oven to 350 degrees. In a hot skillet over medium-high heat, sear each side of tenderloin for 2-3 minutes. Place in the oven and cook for 30-40 minutes or until the meat has reached 160 degrees. Let rest for at least 5 minutes before slicing.

Pan Sauce:
Pan scrapings from pork tenderloin
1/2 cup of chicken broth
2-3 tbsp of pork marinade (thoroughly mixed)
1-2 tsp butter

Meanwhile, place the skillet back on the stove over medium heat. Add the chicken broth and scrape up all the browned pieces from the bottom of the pan. Add the marinade and let it boil down for 2-3 minutes. Add the butter and remove from heat stirring until butter has melted. Pour over the pork tenderloin.