Cook pancetta in a large Dutch oven over medium-low heat 4 minutes until golden brown and crisp. Add onion; cook 5 minutes, stirring occasionally. Add sweet potato and next 4 ingredients. Cover and bring to a boil. Cover, reduce heat, and simmer 15 minutes. Place 3 cups soup 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 blended soup into a large bowl. Repeat procedure with remaining soup. Stir soup to blend. Ladle soup evenly into 6 bowls; sprinkle with Pancetta-Rosemary Croutons.