Best Peanut Brittle

The single most important thing:
You MUST assemble and pre-measure all your ingredients, utensils, and pans in advance

A little practice and the right tools and this will become your most requested holiday treat.

Tools:

2-quart sauce pan
1-candy thermometer
1-heavy duty spatula or bench scraper
1- large baking sheet 21"L x 15"W x 1"H 
1-wooden spoon, no metal, it interacts with the candy and obviously, no plastic (they will melt) 

Ingredients

1 cup white sugar

1/2 cup light corn syrup

1/2 cup water

1-1/2 cups cocktail peanuts

1 tablespoons butter, softened

1 ½ teaspoons baking soda 
1 teaspoon vanilla

Directions

1. Butter a large baking sheet. Set aside.
2. Assemble all equipment and measure out all ingredients BEFORE you start cooking.
3. In a heavy 2 quart saucepan, over medium-high heat (on my stove that's an 8 on the dial), bring to a boil sugar, corn syrup, salt, and water. Stir until sugar is dissolved. Set candy thermometer in place (clipped to the side of the pan with the bulb submerged, but not touching the bottom), and continue cooking without stirring until thermometer reaches 245 degrees.  
4. Stir in peanuts, turn the burner down to medium (6 on my stove dial) and stir constantly until temperature reaches 300 degrees F. Should be golden brown in color.
5. Remove from heat; immediately stir in butter, baking soda and vanilla; 
6. Beat quickly until it foams then immediately pour mixture on to cookie sheet in a sweeping motion from end to end. (do not let the candy all bunch in the middle, it is very hot and will continue to cook if not spread out properly)
7. Use the back of a wooden spoon to quickly spread the candy side to side to stop the cooking process.
8.  Let cool until you can begin to lift the candy around the edges with your spatula or bench scraper. 
9. Keep lifting the edges until you can lift and turn the whole sheet over, one time. 
10. Then begin to quickly pull the candy into a thin sheet. Continue pulling until you have the desired thickness; cool. 
11. Snap candy into pieces. Store in dry, airtight containers or baggies.  Do not seal the container until the candy has completely cooled, 2 or 3 hours.