1- Butter a baking sheet. Butter the sides of a heavy, 2-quart saucepan.
2- In the saucepan, stir together white sugar, brown sugar, cream, milk and
margarine and bring to a boil over medium heat. Heat, without stirring, to
between 234 and 240 degrees F (112 to 116 degrees C), or until a small
amount of syrup dropped into cold water forms a soft ball that flattens when
removed from the water and placed on a flat surface. Remove from heat and
cool to lukewarm (110 degrees).
3- Stir in vanilla and beat vigorously until mixture loses its gloss.
Quickly stir in pecans and spread on prepared sheet. Score into squares
while warm; cut when firm. Makes 24 pieces