1. Bring vinegar to a boil in a small saucepan over medium-high heat. Reduce heat to medium, and cook 6 minutes or until reduced by half. Stir in blackberry preserves, and cook 5 minutes. Stir in salt.
2. Remove silver skin from pork tenderloin, leaving a thin layer of fat covering meat. Cut pork into 8 slices. Place pork between 2 sheets of plastic wrap, and flatten to a 1/4-inch thickness, using a rolling pin or flat side of a meat mallet.
3. Stir together breadcrumbs, pecans, and sage in a shallow bowl.
4. Dredge pork in breadcrumb mixture, dip in beaten eggs, and dredge again in breadcrumb mixture.
5. Cook 4 pork slices in 2 tsp. hot oil in a large nonstick skillet over medium heat 8 minutes or until done, turning every 2 minutes. Repeat procedure with remaining pork and oil. Serve pork over fresh spinach, if desired. Drizzle with vinegar mixture; garnish, if desired.
Note: Nutritional analysis does not include spinach or garnish.