How to Make It
Preheat oven to 325°.
To prepare spice rub, combine first 5 ingredients. Trim fat from pork; rub surface of roast with spice rub. Secure at 2-inch intervals with heavy string.
Heat oil in a large Dutch oven over medium-high heat. Add pork; cook 8 minutes, browning on all sides. Remove from pan. Add onion, leek, and carrot; cover, reduce heat, and cook 5 minutes, stirring frequently. Stir in wine and broth, scraping pan to loosen browned bits. Return pork to pan; add prunes and bay leaves. Bring to a boil. Cover and bake at 325° for 1 1/2 hours or until pork is tender; discard bay leaves.
Place pork on a platter; cover with foil. Remove 6 prunes with a slotted spoon. Place prunes in a food processor or blender; process until smooth. Stir puréed prunes into port mixture. Serve sauce with pork.