¼ cup butter
1-11 oz. can condensed milk
¼ cup corn syrup
1¼ cups brown sugar, packed

 

Grease an 8" cake pan.
In a large heavy saucepan, soften the butter. Stir in remaining ingredients.
Stirring constantly, bring to a boil over medium high heat. Candy thermometer should reach 260º or hard ball.
Stir constantly as it will stick to the pan easily.
Pour into pan quickly and cool. You may make a softer toffee by decreasing cooking time slightly.
Makes 24 pieces.