2. Heat 1 tablespoon oil in a large saucepan over medium heat. Add onion and garlic and cook, stirring, until staring to soften, about 2 minutes. Stir in rhubarb, ketchup, brown sugar, Worcestershire, and ¼ teaspoon black pepper. Bring to a simmer and cook, stirring, until the rhubarb and onion are soft, about 10 minutes. Cover and remove from heat.
3. Meanwhile heat the remaining 1 tablespoon of oil in a large ovenproof skillet over medium high heat. Sprinkle pork with the remaining ¼ teaspoon of black pepper and salt, add to the skillet and cook until browned on all sides about 4 minutes.
4. Transfer the skillet to the oven. Roast the pork until an instant read thermometer inserted into the thickest part reads 145 degrees, about 12-15 minutes. Transfer the pork to a clean cutting board and let rest for 5 minutes. Slice and serve with the rhubarb sauce.