Line a baking sheet with parchment paper and spray with cooking spray.
In a large microwavable safe bowl add the sugar and corn syrup. Stir until combined, mixture will be sticky and hard to stir.
Microwave for 4 minutes on high. Then stir. Microwave for another 3-4 minutes or until mixture starts to turn a light golden color.
Remove bowl from microwave and quickly add peanuts, butter, vanilla and baking soda and mix until combined.
Working quickly spread out on prepared baking sheet.
Let the peanut brittle harden for 30 minutes. Once cooled and hard use your hands to break the brittle into chunks.