Dredge pork in flour, and sprinkle with 1/2 teaspoon salt and black pepper. Heat olive oil in a Dutch oven over medium-high heat. Add pork, and cook for 8 minutes, browning on all sides. Remove from pan.
Add 1 teaspoon fennel seeds to pan, and cook for 30 seconds. Add leek and sliced fennel. Reduce heat to medium, and cook for 10 minutes or until tender. Add vermouth, and cook for 2 minutes or until liquid almost evaporates. Return pork to pan. Add broth, and bring to a boil. Cover, reduce heat, and simmer 1 hour and 45 minutes or until pork is tender. Stir in the remaining 1/4 teaspoon salt. Thinly slice pork.