1Butter or oil an 8 inch square baking pan; set aside.
2Put sugar, vinegar, syrup, and water in a heavy 4 quart saucepan (cast iron if you have it). Gently heat the mixture, stirring with a wooden spoon, until sugar has dissolved and syrup has melted. Bring to a boil, cover and boil for 3 minutes, then remove lid and boil until temperature reaches 285 degrees F (140 degrees C) on a candy thermometer. Remove from heat and stir in the baking soda, mixing well to allow bubbles to subside a little.
3Pour hot mixture into prepared pan and leave until just beginning to set. Mark into squares with a lightly oiled knife. Leave to set completely. Cut or break into pieces.
4Combine chocolate chips, shortening, and baking chocolate in a 2-quart glass bowl. Microwave on High for 2 minutes to melt. Stir with a wooden spoon. Dip candy pieces into chocolate, covering completely. Let cool on waxed paper.
5Wrap individually in waxed paper, twisting the ends together, and store in an airtight container.
Footnotes
Tip
Aluminum foil can be used to keep food moist, cook it evenly, and make clean-up easier.