In a saucepan over medium heat, combine white sugar, brown sugar and milk

Stir in butter and vanilla. Reduce heat between low and medium. Cook for 8-10 minutes, stirring occasionally

Test Syrup: Drop a small amount of syrup into cold water, it should form a soft ball that flattens when removed from water

Remove from heat. Add pecans, then beat until thickened. Pour immediately onto wax paper and let rest until firm about 15 minutes