Melt butter in large saucepan on medium heat. Add broccoli; cook 2 min., stirring frequently. Stir in flour until blended; cook 2 min. or until hot and bubbly, stirring constantly. Gradually stir in dressing, then milk. Bring to boil on medium heat, stirring constantly; cook and stir 2 min. or until thickened. Remove from heat; stir in cheese.