Sauté onion in oil in saucepan about 3 minutes or until tender.
Add 3 cups broth. Bring to boiling. Add cauliflower. Return to boiling. Reduce heat to medium; cook about 6 minutes or until almost tender.
Whisk together flour and the remaining 1 cup chicken broth in a small bowl. Stir into saucepan. Bring to boiling; cook, stirring occasionally, for 2 to 3 minutes or until thickened.
Remove soup from heat. Add cheese, stirring until melted. Stir in roasted red peppers, salt and hot-pepper seasoning, breaking up red peppers with a wooden spoon.
