1Generously grease large cookie sheet and wooden spoon with butter.
2In 2-quart nonstick saucepan, heat corn syrup, sugar and water to boiling, stirring frequently. Boil 10 to 15 minutes, stirring frequently, until mixture reaches 230°F to 234°F on candy thermometer and forms a long thread when spoon is lifted and held above pan. Stir in peanuts. Cook 10 to 15 minutes longer, stirring frequently, until peanuts turn golden brown and mixture reaches 300°F.
3Meanwhile, in small bowl, stir vanilla and baking soda until soda is dissolved. Remove saucepan from heat; stir in vanilla mixture and butter. Quickly spread on cookie sheet, smoothing top with back of buttered spoon to make a single layer of peanuts. Cool about 20 minutes; break into 1-inch pieces. Store in airtight container up to 3 weeks.