Prep Time: 5 minutes
Cook Time: 20 minutes
Cook bacon in large saucepan over medium heat until crisp. Use a slotted spoon to transfer bacon to paper towel-lined plate; set aside. Pour off all but 2 tablespoons drippings from saucepan.
Cook onion in drippings, stirring occasionally, until tender, 4 to 5 minutes. Add flour and cayenne pepper; cook and stir 1 minute. Stir in milk and broth. Bring to boil over high heat, stirring occasionally. Reduce heat; simmer 5 minutes, stirring occasionally. Remove from heat; stir in 1-1/2 cups cheese until melted.
Ladle into bowls; top with reserved bacon and remaining cheese.