Preheat the oven to 200 degrees F.
Heat the oil in a large skillet. Season lamb with salt and pepper and pan-sear to the desired doneness, allowing 3 to 4 minutes per side for medium rare to medium. Transfer the lamb to a heat-proof plate and keep warm in the oven.
Drain excess fat from the skillet and set back over the heat. Combine remaining ingredients in a bowl. Pour this mixture into the skillet, bring to a simmer, and simmer until a thickened sauce forms. Plate the lamb, top with sauce and serve.