Bring potatoes, onions and broth to a boil in a large saucepan; simmer for 15 minutes.
Remove half of the potatoes and onions; set aside.
Place the remaining potatoes, onions and broth mixture into a blender or food processor (or use an immersion blender) and blend until smooth. (if using a food processor or blender, work in small batches to avoid overflow due to heat). Return to saucepan along with chunky potatoes and onions.
Melt butter in a separate saucepan. Stir in flour; cook and stir 1 minute. Add milk; cook and stir until smooth and thickened. Add to potato-broth mixture along with the corn, bacon and spices; simmer 5 minutes.