Steam broccoli and cauliflower, covered, 5 minutes or until crisp-tender.
Drain well; set aside.
Combine breadcrumbs and next 5 ingredients; stir well, and set aside.
Place flour in a small saucepan. Gradually add milk, stirring with a whisk until blended. Bring to a boil over medium-high heat, and cook 1 minute or until thick, stirring constantly.
Remove from heat; add cheese, stirring until cheese melts.
Combine vegetables and cheese sauce, stirring well to coat. Spoon mixture into a 1-quart baking dish coated with cooking spray.
Sprinkle with breadcrumb mixture.
Bake at 375 for 25 minutes or until breadcrumbs are lightly browned.