Two important facts about peanut brittle: 1.) It is easy to make great peanut brittle. 2) It is easy to make terrible peanut brittle.
To make the great stuff, boil together three cups of sugar, one cup of light corn syrup, and one-half cup water. USE A CANDY THERMOMETER. While it’s heating up, butter a one-half sheet pan. At 230 degrees F (soft ball), add three cups of raw peanuts and a generous pinch of salt, and stir the mixture constantly as it cooks. At 300F (hard crack), add three tablespoons of room-temperature butter and turn off the heat. Quickly stir in a generous tablespoon of vanilla extract, then three teaspoons of baking soda. When the soda is mixed in and the whole thing is a big foamy mass, quickly turn it out onto the buttered sheet pan and tilt the pan so the corners fill in. Let it cool, and all that’s left is the breaking up and the eating.
To make terrible peanut brittle, follow the above directions exactly during humid weather. The sugar crystals will seize all available water vapor right out of the air, and you’ll be left with a nasty product that is sticky to the touch, not entirely brittle, and guaranteed to get in your teeth and never go away. Make this during clear, cloudless days and you’ll have a great candy that will melt in your mouth after the first crunch with caramelly, roasty-peanutty, buttery goodness. The perfect sweet for chocolate-haters.