Line a rimmed baking sheet with parchment paper and keep warm in a 250°F oven.

Measure out the peanuts, baking soda, butter, and vanilla. Set them aside and have them ready, to add to the syrup. You’ll need to work quickly once the sugar syrup reaches 300°

Combine the sugar, corn syrup, salt, and water in a medium saucepan. Heat over medium heat, stirring until the sugar is dissolved, then attach a candy thermometer to the side of the pan. Don’t let the tip of the thermometer touch the bottom of the pan.

Bring to a boil and let the syrup gently boil without stirring until it reaches 280° Have patience and cook on medium heat. Turning it higher can cause the mixture to burn.

Stir in the peanuts and continue cooking on medium-low heat until the temperature reaches 300°

Working quickly, stir in the butter, vanilla, and baking soda. The baking soda will foam and bubble up. Immediately pour onto the prepared, warm baking sheet in a zig zag pattern, tilting the pan from side to side to evenly distribute the mixture. If necessary, spread the mixture out with 2 forks or a spatula.

Let cool completely. Break the candy into pieces.

Store at room temperature in an airtight container.