It is helpful to butter the foil, measure soda, vinegar and vanilla before you start. Once you take it off the stove, you can't stop. You have to stir constantly while boiling, otherwise it will burn.

In large heavy pot (3 quart) :

2 c. sugar
1 c. white Karo syrup
3/4 stick butter

(Note: Do not use butter because it will burn). Bring to a boil and cook until it reaches 280 degrees on candy thermometer. Then add 1 (13 ounce) can Spanish peanuts (stir in). Bring to a boil and cook until reaches 280 degrees on candy thermometer.

Turn off burner and add:

2 tsp. baking soda
1 tsp. vanilla
1 tsp. vinegar

Stir fast until it turns a deep gold color - spread out on buttered foil and cool. Break into pieces and store in closed container.