Line a rimmed baking sheet with parchment papers or a silicone mat.
In a large heavy saucepan, stir together sugar, corn syrup, and water.
Measure peanuts, butter, vanilla, and baking soda and have it ready to add.
Add a candy thermometer to the side of the saucepan. Cook over medium heat until temperature reaches 240° F on the thermometer.
Add peanuts and stir constantly until the temperature reaches 280° F.
Add butter and continue to stir until the temperature reaches 300° F.
Remove from heat and add vanilla and baking soda, stirring constantly
Pour immediately onto prepared baking sheet and spread as evenly as possible
Cool completely. Break into pieces. Store in an airtight-container.