Heat oil in a large Dutch oven over medium heat. Add leek; cook 15 minutes or until tender, stirring frequently (do not brown). Set aside.
Combine broth, potato, and cauliflower in pan; bring to a boil. Reduce heat, and simmer 25 minutes or until potato is tender. Cool 10 minutes; stir in milk. Place one-third of potato mixture in a blender; process until smooth. Pour pureed potato mixture into a large bowl. Repeat procedure twice with remaining potato mixture.
Return pureed potato mixture to pan; stir in leek, pepper, salt, and corn. Cook over medium-high heat 5 minutes or until thoroughly heated, stirring frequently. Sprinkle with crumbled bacon just before serving.