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.
I removed the excess oil from the frying pan in which the pork was cooked using a paper towel On a medium flame, I deglazed the brown bits from the bottom of the pan ("fond") with a 1-2 tsp of red wine vinegar and let cook down until it was almost dry. Then I added the rosemary flavored red wine reduction (4 tbs). I also added any juices that may have accumulated on the plate on which the pork was resting. I seasoned the sauce with a bit of sugar, salt and pepper. I finished the sauce with several pats of butter. Another sauce that we use, especially if the meat is cooked in one of the other two ways and there is no "fond" to deglaze, is a simply reduced balsamic vinegar.
Since I had leftover fennel (1/3 bulb), red onion (1/2 medium), and sweet potato (1/3, medium), I just cut them up in equal sized strips and sauteed them in olive oil with salt and pepper and placed the frying pan in the same oven to finish as an accompaniment. The "presentation" of this dish, as shown in the picture, could stand some improvement but it did taste good.