How to Make It
Heat 1 tablespoon oil in a large nonstick skillet over medium-high. Add shallots, garlic, and thyme; cook 5 minutes, stirring often, until shallots are caramelized. Add spinach; cook 1 minute, stirring constantly, until wilted. Remove from heat.
Combine goat cheese, chives, parsley, and lemon rind in a small bowl.
Holding knife flat and parallel to cutting board, cut horizontally through center of pork loin, cutting to, but not through, other side. Open flat, as you would a book. Starting at the center seam, cut horizontally through each half, cutting to, but not through, other side. Open flat on either side. Place pork between 2 sheets of plastic wrap; pound to an even 1/2-inch thickness using a meat mallet or small, heavy skillet. Remove plastic wrap.
Season with 1/2 teaspoon salt and 1/2 teaspoon pepper. Spread goat cheese mixture evenly over pork; top with shallot mixture. Roll up pork jelly-roll fashion. Tie with kitchen twine at 1-inch intervals. Sprinkle with remaining 1 teaspoon salt and remaining 1/2 teaspoon pepper.
Wipe pan clean. Heat remaining 1 tablespoon oil over medium-high. Add pork; cook 3 minutes per side or until browned. Place stuffed pork in a 5-quart slow cooker.
Add apricot preserves, butter, and mustard to pan; reduce heat to medium. Cook 1 minute, stirring constantly, until butter melts. Pour over pork loin in slow cooker. Cover and cook on LOW 7 to 8 hours, or until a meat thermometer inserted in thickest portion of pork registers 145°F.
Place pork on a cutting board; let stand 15 minutes. Skim and discard fat from sauce in slow cooker. Pour sauce into a saucepan; bring to a boil over medium-high. Cook 5 minutes, until reduced to about 1 cup. Stir in vinegar.
Remove and discard twine. Slice pork into 12 slices; serve with sauce.