1. Remove root, tough outer leaves, and tops from leek, leaving 2 inches of dark leaves. Thinly slice leek; rinse well, and drain.
2. Cook bacon in a large Dutch oven over medium-high heat 8 to 10 minutes or until crisp; remove bacon, and drain on paper towels, reserving 2 Tbsp. drippings in Dutch oven. Crumble bacon.
3. Sauté leek, celery, and garlic in hot drippings 3 to 4 minutes or until tender. Add chicken broth, zucchini, and potatoes, and simmer 20 to 25 minutes. Stir in half-and-half, parsley, salt, and pepper. Remove from heat, and cool 5 minutes.
4. Process potato mixture, in batches, in a blender or food processor until smooth, stopping to scrape down sides as needed. Sprinkle with crumbled bacon, and serve immediately, or if desired, cover and chill 4 to 6 hours.