Sponge Candy
["1 c. granulated sugar", "1 c. dark corn syrup", "1 Tbsp. cider vinegar", "1 to 1 1/2 Tbsp. baking soda", "chocolate disks"]
["Combine sugar, corn syrup and vinegar in heavy kettle.", "Use a candy thermometer and boil (medium heat) to 300\u00b0.", "Mixture will look as if it is going to burn.", "Remove from heat and add baking soda.", "(It is best to sift the soda; lumps will not break with stirring.)", "Immediately start stirring very, very quickly and pour mixture into a thoroughly buttered 8 x 12-inch baking pan.", "Allow mixture to cool for at least 4 hours, then break or cut into pieces and dip in melted chocolate."]
["sugar", "corn syrup", "cider vinegar", "baking soda", "chocolate disks"]