Grandma Stahle's Caramels

4 cups sugar
1/2 lb. butter
2 cups white corn syrup
2 tall cans evaporated milk
2 t. vanilla

Stir sugar, butter, and syrup in a heavy pan. Cook over medium heat until mixture boils well. Add evaporated milk a little at a time so mixture doesn't stop boiling. Stir constantly with a wooden spoon. Cook to 230 degrees. Remove from heat and add vanilla. Do not scrape sides or bottom of pan into finished caramel. Pour into buttered pan and cool. Cut into small squares and wrap each piece in waxed paper.