SAUTE squash, onions and garlic in dressing in large skillet on medium-high heat 5 min. or until lightly browned. Stir in broth. Bring to boil. Reduce heat to low; simmer 20 min. or until squash is tender, stirring occasionally.
PROCESS soup, in batches, in food processor until smooth. Pour into large stockpot. Cook on low heat until heated through, stirring occasionally.
FOR each serving: Pour 1 cup hot soup into serving bowl. Top with 1 Tbsp. sour cream, 1 oz. cheese and 1 Tbsp. onions. Sprinkle with 1 crumbled bacon slice.