Cinnamon Walnut Brittle

Butter a baking sheet; set aside. In a 2-qt. microwave-safe bowl, combine sugar and corn syrup. Microwave, uncovered, on high for 3 minutes; stir. Cook, uncovered, on high 2-1/2 minutes longer. Stir in the walnuts, butter and cinnamon. , Microwave, uncovered, on high for 2 minutes longer or until mixture turns a light amber color (mixture will be very hot). , Quickly stir in baking soda and vanilla until light and foamy. Immediately pour onto prepared pan; spread with a metal spatula. Cool; break into pieces.