Mix pet milk and sugar (equal parts of cream and sugar if you are adding to recipe). Boil until thermometer reaches 210F and add butter or margarine and vanilla extract. When temperature reaches soft ball stage add 1-1/2 cups pecans. When temperature reaches 2 degrees higher than soft ball stage, turn heat off and whip until it feels heavy. Spoon on buttered platter by spoonfuls. Allow to cool.
NOTE: If doubling recipe, cook 2 degrees higher. Soft ball stage is 235F