In 1 1/2-quart microwavable casserole, cook broccoli as directed on package; drain.
Stir in macaroni and cheese, and sausage. Microwave on High 6 to 8 minutes or until thoroughly heated, stirring once or twice.
In small microwavable bowl, microwave butter on High 25 to 30 seconds or until melted. Stir in crushed crackers; sprinkle over top of macaroni mixture.
Microwave casserole on High 1 to 3 minutes or until crumbs are hot.