Grease a 12×15 inch pan (I split it between a 13×9 inch and a 8×8 inch pan. Just use what you have on hand!) Set aside.
Combine all of the ingredients in a large saucepan. Place a candy thermometer into the saucepan. Heat the mixture on medium low, stirring constantly. Continue stiring, keeping an eye on the mixture until it reaches 250˚F. (This will take a long time a long time. Don’t rush it!)
Immediately pour the mixture into your prepared pan(s). Allow the mixture to cool. Cut into squares with a sharp knife or scissors.