Preheat oven to 350°.
Arrange corn bread in a single layer on a baking sheet. Bake at 350° for 15 minutes or until golden brown.
Heat a large saucepan over medium heat. Add bacon to pan; cook 5 minutes or until crisp, stirring occasionally. Remove bacon from pan, reserving 1 tablespoon drippings in pan. Set bacon aside. Add onion and garlic to drippings; cook 8 minutes or until tender, stirring occasionally. Stir in peas and next 5 ingredients (through pepper); bring to a boil. Cover, reduce heat, and simmer 40 minutes or until beans are very tender.
Place half of bean mixture 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 pureed soup into a large bowl. Repeat procedure with remaining bean mixture. Ladle about 1 1/3 cups soup into each of 6 bowls; top each serving with about 2 1/2 tablespoons watercress, 2 1/2 tablespoons croutons, and about 1 1/2 teaspoons bacon.