Line a large cookie sheet with parchment paper and spray with nonstick cooking spray. Set aside.
In a medium saucepan, stir together the sugar, corn syrup water and salt then bring to a boil over medium heat. Hook the candy thermometer to the inside of the saucepan.
When the sugar comes to a boil (about 6 to 7 minutes) add the sliced butter. Stir to combine.
Let the mixture come back up to a boil until it reaches 280°F. Then stir in the peanuts.
Continue boiling the mixture until the candy thermometer reads 300°F.
Remove from heat and stir in the baking soda.
Immediately pour the mixture into the prepared cookie sheet and smooth it out.
Let cool completely. Break into pieces and store in an airtight container. Enjoy!