We cook this very often and we use the leftovers for sandwiches and other dishes. We cook this in several different ways depending on the situation, although the initial preparation is the same. I use packaged pork tenderloin (usually two in the package) and season it with rosemary, salt and black pepper. We cook this one of three ways: 1) In a low-temperature oven (350F) for 1 hour with other vegetables (sweet potato, onion, garlic-clove separated but with skin still on, carrot etc. coated with olive oil, 2) Seared first in a frying pan and finished in a 400F oven, 3) Using a Weber grill. The end products are slightly different but all are good in their own way.
Preparation: After removing the silver skin and the ends (tail and head) of the tenderloins (I use these cut off portions for other pork dishes), you will have two nice cylinders with an even diameter throughout the length of the loins. I finely chop fresh rosemary (2 tbs) and mix it with olive oil (4 tbs) and coat the surface of the meat generously and season it with salt and freshly cracked black pepper. This time I used the method #2 above. I added olive oil (1 tbs) to a frying pan on a medium high flame and seared the surface all round by turning 90 degree once one side is nicely browned. Then I put it in a 400F preheated oven for about 10 minutes or until internal temperature reads 145F at the center of the loin. I remove the meat and keep it warm on a plate under a tent of aluminum foil.
Sauce: I made a red wine reduction with a sprig of rosemary in it ahead of time and used it on the pork. I made this reduction since I had leftover red wine (called “Cheap Red Wine”). I reduced it to 1/4 of the original volume with a sprig of fresh rosemary in it.