Remove and discard broccoli leaves; cut off and discard tough ends of stalks. Wash broccoli; cut into spears. Arrange spears in a steamer basket over boiling water. Cover and steam 8 minutes or until broccoli is crisp-tender.
Drain and place on a serving platter; set aside, and keep warm.
Melt margarine in a saucepan over medium heat.
Add milk and next 3 ingredients; cook, stirring constantly with a whisk, until smooth.
Add cheese and caraway seeds; cook, stirring constantly, until cheese melts and mixture is thickened and bubbly.