Spray a baking sheet and a wooden spoon with cooking spray.
Mix sugar and corn syrup together in a microwaveable bowl safe for high temperatures.
Heat sugar mixture in microwave on high for 5 minutes.
Stir peanuts and butter into sugar mixture. Heat in microwave until mixture becomes a caramel color, 3 to 4 minutes.
Mix baking soda and vanilla extract into syrup until smooth and foam has dissipated. Spread candy onto the prepared baking sheet using the sprayed wooden spoon. Work quickly; candy hardens fast. Let stand until cool. Break into pieces to serve.
