Spray a rimmed cookie sheet with cooking spray and set it aside.
In a 2 L (2 quart) glass bowl stir together sugar and corn syrup with a wooden spoon until mixed well. Microwave on high or 100% for 6-8 minutes until syrup is pale yellow. Keep a close eye on it!!
Carefully remove the bowl from the microwave, the syrup is very hot. Stir in the peanuts and mix well.
Microwave for 1-2 min. more or until golden in color. Immediately add the butter, vanilla, and baking soda and stir until foamy.
Quickly pour onto the prepared cookie sheet and spread evenly.