While the sugar mixture boils, mix together the baking soda and salt in a small bowl. Mix together the teaspoon of water and vanilla in a separate bowl. Do not mix these two together yet, but keep a spoon nearby for mixing. Put these right next to the stovetop, within arms reach of the sugar mixture, which you should continue to stir occasionally.

While the water continues to boil out is a good time to prep for the ending. You'll need two cookie sheets, liberally buttered, or two silpats. Put them right next to each other and in an easy place to reach. You've gotta be able to pour this mixture up quickly at the end. Don't forget to occasionally stir your sugar mixture.

Continue stirring the mixture occasionally. When all the water has boiled away the temperature will start to creep upward again. When the temperature hits 240°F, toss in the butter and peanuts. The temp will drop quite a bit when you do this but it'll recover quickly. From this point forward you MUST STIR CONSTANTLY! All those peanuts are going to make the mixture much harder to stir and you'll probably have to hold your thermometer in place, but do your best. I like to put an oven mitt on my left hand, grip the pot handle for stability, and use my fingers to wedge the thermometer in place at the same time, leaving my right hand free to stir CONSTANTLY.

Alright, as soon as we hit 300°F you've gotta work very quickly! At 300°F, move the pan off of the heat and toss the thermometer out of the way. CAREFUL, that sticky mixture is deadly hot! Give your water/soda mixture a quick stir and toss it into the pot. It's going to hiss and foam and go absolutely crazy, so don't get burned! Quickly stir it together just enough to mix thoroughly but don't take too long or you're gonna have a mess. As soon as its mixed together, pour half out onto each of your pans or silpats. Do not spread! It'll look thick and puffy, but let it do its own thing and it'll all work out.

Let this cool for a while and it'll break right up, but it'll be slightly sticky in your teeth for 10-15 minutes as the sugars fully set. Its still good, but its not its best until its fully set. Now is a good time to clean up your pots and utensils, but its not hard. Some hot water will quickly dissolve all that sugary mess.