Pork Tenderloin with Plum Sauce

Preheat your oven to 400 degrees Fahrenheit (200 degrees Celsius).

Heat a generous amount of oil in a large, oven-safe skillet over high heat. Season the pork tenderloin generously with salt and black pepper before cooking it in hot oil until it's browned on all sides, taking about 2 to 4 minutes per side. Transfer the tenderloin to a plate and set it aside.

Sauté sliced onions and a pinch of salt in the skillet's drippings until they begin to soften, taking around 3 to 5 minutes. Add minced shallots and reduce the heat to medium before cooking and stirring until the onions and shallots are golden brown and caramelized, approximately 10 minutes.

Stir in some dried thyme before placing the tenderloin on top of the onion mixture. Arrange sliced plums, skin-side down, around the tenderloin. Transfer the skillet to the preheated oven.

Cook until the pork is slightly pink in the center, taking around 20 minutes. An instant-read thermometer inserted into the center should read at least 145 degrees Fahrenheit (63 degrees Celsius). Transfer the pork and plums to a clean plate, cover them with aluminum foil to keep warm, and let it rest.

Place the skillet over high heat. Pour water and vinegar into the onion mixture, then bring it to a boil while scraping the browned bits of food off the bottom of the pan with a wooden spoon. Cook and stir until the liquid is reduced by half, taking around 5 to 10 minutes. Remove from heat and whisk in cold butter until it's melted and the sauce is shiny.

Pour the sauce over sliced pork and plums to serve.