butter or margarine
chopped yellow onions
(14-1/2 oz.) fat-free reduced-sodium chicken broth
baking potatoes (about 2), baked, cut into 1/2-inch pieces
green onion, sliced, divided
cooked OSCAR MAYER Center Cut Bacon, crumbled, divided
KRAFT Finely Shredded Mild Cheddar Cheese, divided
Melt butter in large saucepan or Dutch oven on medium heat. Add yellow onions and celery; cook and stir 5 min. or until crisp-tender. Add next 4 ingredients; bring just to boil, stirring constantly. Lightly crush potatoes with back of spoon. Simmer on medium-low heat 5 min., stirring frequently.
Reserve 1 Tbsp. green onions and 2 Tbsp. bacon and cheese. Add remaining green onions, bacon and cheese to soup; cook 5 min. or until cheese is melted, stirring constantly.
Serve topped with reserved green onions, bacon, cheese and sour cream.