Grease two cookie sheets with butter and place in a 200 degree oven to keep warm.
In a small dish stir together baking soda, 1 teaspoon water, and vanilla - reserve.
In another small dish place butter and salt- reserve.
In a 3 quart saucepan pour sugar, water, and corn syrup. Place a candy thermometer in the mixture and heat over medium, stirring intermittently, until mixture reaches 240 degrees.
Then, add the butter and salt, and then begin stirring constantly.
Watch the temperature very closely - your goal temp is 300 degrees. I took the baking sheets out of the oven at 280 degrees, and dumped in the peanuts at 290 degrees. (Adding the peanuts late in the game prevents the nuts from burning).
When your peanut candy mixture reaches 300 degrees, immediately turn off the heat and pour in the baking soda mixture.
Stir until everything is combined and color turns pale orange and foamy.
Quickly pour evenly between the 2 greased cookie sheets.
Spread with a spatula to desired thickness.
Cool for 1 hour, then break into pieces.