In a medium saucepan combine brown sugar, sugar, condensed milk and butter. Heat to 250 to 265 degrees F (121 to 129 degrees C), or until a small amount of syrup dropped into cold water forms a rigid ball.
Pour into an 8x8 inch pan. Cool until firm and cut into squares.
Per Serving: 53 calories; protein 0.5g; carbohydrates 8.7g; fat 2g; cholesterol 5.9mg; sodium 18.6mg.