1
: Line a 10" x 15" baking sheet with sides with parchment paper.
2
: Combine sugars, corn syrup, evaporated milk and butter in medium saucepan. Place on medium heat and stir mixture constantly until it comes to a boil. Stir and boil constantly, until mixture reaches 236°F on candy thermometer, about 15 minutes. Remove from heat and cool 10 minutes. Carefully stir in vanilla and pecans and continue stirring 2 minutes, to cool down mixture. Pour onto prepared baking sheet and spread mixture to about 1/4" thick. Let cool. Break into pieces.