Prepare baking sheet, spray with nonstick cooking spray. Microwave sugar and corn syrup in a glass bowl for 4 minutes. Add peanuts and butter, stirring with a heatproof utensil.
Microwave the bowl until caramelized, then add vanilla and baking soda, stirring quickly. Stir until combined, avoiding over-stirring, as this helps create a lighter honeycomb texture.