Preheat oven to 400°.
Cook bacon in a nonstick skillet over medium heat until crisp. Remove bacon from pan; crumble. Set aside. Add onion and thyme to bacon drippings in pan; sauté 6 minutes over medium-high heat until lightly browned. Stir in pepper. Place crust on a baking sheet. Spread Alfredo sauce over crust; top with onion mixture, clams, bacon, and cheese. Bake at 400° for 12 minutes or until cheese melts. Sprinkle with parsley.