In 4-quart saucepan, heat 2 quarts water to boiling over high heat. Meanwhile, in small bowl, stir together butter, chives, thyme, lemon peel, salt and pepper until blended; set aside.
Add cauliflower to boiling water in saucepan; cook 2 minutes. Add broccoli; cook 2 to 3 minutes longer or until vegetables are crisp-tender. Drain; return to saucepan.
Add butter mixture to vegetables in saucepan; toss to coat.