1. Fill a large Dutch oven with water to depth of 1/4 inch. Arrange cauliflower in Dutch oven. Cook, covered, over medium-high heat 7 to 10 minutes or until tender. Drain.
2. Process cauliflower, sour cream, salt, and pepper in a food processor 30 seconds to 1 minute or until smooth, stopping to scrape down sides as needed. Stir in Parmesan cheese and chives. Place in a bowl.
3. If desired, microwave mixture at HIGH 1 to 2 minutes or until thoroughly heated, stirring at 1-minute intervals.
4. Cook butter in a small heavy saucepan over medium heat, stirring constantly, 4 to 5 minutes or until butter begins to turn golden brown. Remove from heat, and immediately drizzle butter over cauliflower mixture. Garnish, if desired. Serve immediately.
*2 (16-oz.) bags frozen cauliflower may be substituted. Cook cauliflower according to package directions. Proceed with recipe as directed, beginning with Step 2.