1. Preheat oven to 350°.
2. Remove white papery skin from garlic head (do not peel or separate the cloves). Wrap head in foil. Bake at 350° for 45 minutes; cool 10 minutes. Separate cloves; squeeze to extract garlic pulp. Discard skins.
3. Place parsley, thyme, leek leaves, and bay leaf on cheesecloth. Gather edges of cheesecloth together; tie securely.
4. Heat oil in a Dutch oven over medium heat. Add sliced leek to pan; cook 7 minutes or until wilted, stirring occasionally. Stir in bread and chopped raw garlic; cook 2 minutes. Add herb bundle, broth, and pepper; bring to a boil. Reduce heat, and simmer 10 minutes, stirring occasionally; discard herb bundle.
5. Place half of leek mixture and half of roasted garlic pulp in a blender. Remove center piece of blender lid (to allow steam to escape); secure blender lid on blender. Place a clean towel over opening in blender lid (to avoid splatters). Blend until smooth. Pour into a large bowl. Repeat procedure with remaining leek mixture and roasted garlic pulp. Ladle about 2/3 cup soup into each of 6 bowls; sprinkle each serving with 2 teaspoons chives.