Grease a large cookie sheet (better, yet, use a Silpat mat). Set aside.

In a heavy 2 quart saucepan, over medium heat, bring to a boil sugar, corn syrup, salt, and water.

NOTE: Using a candy thermometer, I waited until the hot liquid reached 250°F. Reviews suggested this, so that I didn't risk burning the peanuts.

Stir until sugar is dissolved. Stir in peanuts. Set candy thermometer in place, and continue cooking. Stir frequently until temperature reaches 300°F (150°C), or until a small amount of mixture dropped into very cold water separates into hard and brittle threads.

Remove from heat; immediately stir in butter, vanilla and baking soda; pour at once onto cookie sheet. With 2 forks*, lift and pull peanut mixture into rectangle about 14x12 inches; cool.

*I just tilted the brittle, as soon as it was poured on my Silpat and it distributed evenly.

Snap candy into pieces.