Line three 15-in. x 10-in. x 1-in. pans with parchment paper. (Do not spray or grease.)
In a large heavy saucepan, combine the sugar, water and corn syrups. Bring to a boil, stirring constantly to dissolve sugar. Using a pastry brush dipped in water, wash down the sides of the pan to eliminate sugar crystals. Cook, without stirring, over medium heat until a candy thermometer reads 260° (hard-ball stage).
Stir in peanuts and butter; cook to 300° (hard-crack stage), about 9 minutes longer, stirring frequently.
Remove from the heat; stir in baking soda and vanilla. (Mixture will foam.) Immediately pour into prepared pans, spreading as thin as possible. Cool completely. Break into pieces. Store between layers of waxed paper in airtight containers. Yield: 2-3/4 pounds.