In a saucepan, heat the peanut butter to 100°C/212°F. Remove from the heat and stir in the glucose syrup. Keep the mixture warm.
To Make the Hard Candy Base
Combine the sugar and water in a heavy saucepan and bring to a boil. Add the glucose syrup and cook to 130°C/266°F.
Add the molasses and salt and cook to 155°C/311°F.
Remove from the heat and stir in the baking soda.
Pour onto an oiled marble slab and turn occasionally until cooled to a plastic consistency. Pull until well aerated.
Divide the pulled sugar into two portions: one 60 percent of the batch, the other 40 percent. Keep each portion warm under a warmer or in a low oven.
Stretch the larger piece of sugar into a rectangle approximately 18 × 25cm/7 × 10in. Place the peanut butter filling in the center and roll the sugar over the filling to make a cylinder. Seal the ends to encase the filling.
Stretch the filled cylinder to 61cm/24in, then fold it back in half. Repeat this eight times. Return to a cylindrical shape. Fold again if necessary to make a stubby log approximately 18cm/7in long.
Stretch the smaller piece of sugar into a ribbon 10cm/4in wide. Pull to 61cm/24in long. Cut and attach the two halves side by side. Repeat a total of four times to make a thin, even layer that is approximately 23 × 30cm/9 × 12in. This is the jacket for the candy.
Wrap the jacket around the filled cylinder.
Cut off the ends of the cylinder, which contain no filling. Discard them or rework them into the next batch.
Pull into a rope 6mm/¼in in diameter and cut into 5-cm/2-in segments. Drop segments into desiccated coconut immediately.