Prepare baking sheet by greasing it with butter
In a large pot with candy thermometer attached, add sugar, corn syrup, and hot water. Bring to a boil over medium heat. Boil until the candy thermometer reaches 250 degrees F.
Add peanuts and butter and stir continuously until your thermometer reaches 308 degrees F.
Remove from heat and add the baking soda and vanilla. This will bubble up, so stir quickly to incorporate it into the whole mixture.
Quickly pour onto your prepared baking sheet.
Place baking sheet in a cool area to cool down completely. This can take up to 2 hours.
Break peanut brittle into pieces using you hands. Store in an air-tight container for up to 2 weeks or more.
