Roasted Pork Tenderloin with Fresh Plum Sauce

Step 1
Preheat the oven to 400 degrees F (200 degrees C).

Step 2
Heat oil in a large, oven-proof skillet over medium-high heat. Generously season pork tenderloin with salt and black pepper. Cook tenderloin in hot oil until browned on all sides, 2 to 4 minutes per side. Transfer tenderloin to a plate and set aside.

Step 3
Saut? onion and a pinch of salt in drippings in the skillet until onion begins to soften, 3 to 5 minutes. Add shallots; reduce heat to medium. Cook and stir until onion and shallots are golden brown and caramelized, about 10 minutes.

Step 4
Stir thyme into onion mixture, then place tenderloin on top. Set plums, skin-side down, around tenderloin. Transfer the skillet to the preheated oven.

Step 5
Cook until pork is slightly pink in the center, about 20 minutes. An instant-read thermometer inserted into the center should read at least 145 degrees F (63 degrees C). Transfer pork and plums to a clean plate; cover with aluminum foil to keep warm.

Step 6
Place the skillet over medium-high heat. Pour water and vinegar into onion mixture. Bring to a boil while scraping the browned bits of food off of the bottom of the pan with a wooden spoon. Cook and stir until liquid is reduced by half, 5 to 10 minutes. Remove from heat. Whisk in cold butter until melted and sauce is shiny.

Step 7
Pour sauce over sliced pork and plums to serve.