Mix broth and soup in a large saucepan. Bring to a boil over medium-high heat. Add broccoli; return to a boil and reduce heat. Simmer, covered, for 5 minutes or until broccoli is tender.
Heat butter in a medium skillet over medium heat; add onion. Saute until tender, about 6 minutes. Add flour. Cook for 1 minute longer. Gradually stir milk into skillet. Cook, stirring continually, until thickened, about 5-6 minutes. Add salt and pepper; mix well.
Stir milk mixture into broccoli mixture. Add a handful of Kraft Sharp Cheddar Cheese. Simmer, covered, over low heat, stirring occasionally, for about 15 minutes. Ladle soup into a serving bowl. Top with Kraft Sharp Cheddar Cheese, about a handful in each individual serving.