For this recipe, you will need a candy thermometer. Tips: Pre-measure and set aside the baking soda, butter and vanilla – you will need to add them quickly when the time comes. Spray a large, clean baking pan with non-stick spray. And put some hot water and a pastry brush nearby the stove. And be careful – boiling sugar is very hot! In a larger saucepot, over med-high heat, stir together sugar, corn syrup, water and salt. When melted, stop stirring and, washing down sides with a pastry brush dipped in water, simmer until temperature reaches 240°F. Meanwhile, warm the peanuts in the microwave a couple of minutes so they don’t cool down the mixture when added. When sugar mixture reaches 240°F, stir in the peanuts. Stirring well every so often (so nuts don’t burn), continue cooking until temperature reaches 300°F. Remove from heat and quickly stir in the soda, butter and vanilla. It will froth and bubble. Immediately, spread mixture onto greased baking sheet. Do not refrigerate! It will make your brittle sticky. Let cool on counter at room temperature. Break into pieces and store in airtight container (again, not in fridge).