Begin by preparing a sheet pan with parchment paper or a silicone mat .
In a large non-stick pot, combine sugar and water, stirring until well mixed. Pour the corn syrup into the mixture and give it a good stir, then gently bring it to a boil over medium-low heat stirring every few minutes to ensure it doesn’t stick to the bottom. Use a candy thermometer and measure it until it reaches 250°F.
Pour the peanuts into the mixture and carry on stirring until it reaches a temperature of 300°F.
Take the pot off the heat and add the butter, baking soda, and vanilla. Stir until it starts to bubble and change consistency.
Carefully pour the mixture onto the prepared baking sheet. Allow it to cool and set; this should take around 45 minutes.
Once it has solidified, either cut or break the mixture into pieces and store them in an airtight container.