MICROWAVE sugar and corn syrup in large microwaveable bowl on HIGH 5 min., stirring after 3 min. Stir in peanuts. Microwave an additional 3 to 5 min. or until golden brown.
ADD butter and vanilla; stir until butter is completely melted. Microwave 1 min. Stir in baking soda. (Mixture will foam.)
SPREAD mixture onto baking sheet. Cool completely. Break into pieces.