Take a large mug of caster sugar, two table spoons of golden syrup, two table spoons of water and a teaspoon of vinegar and boil without stirring until the water has evaporated and the sugar begins to show signs of caramelising, ie it starts to become a little browner. This takes 5-10 mins depending on the heat setting and can take a little practice to get right. Remove from heat and quickly add 3 1/2 teaspoons of sodium bicarbonate and whisk vigourously for 5-10 seconds. Pour into a deep tray lined with grease proof paper and leave to set. Break it up and serve, or coat the larger pieces in chocolate. Cooking chocolate melted in the microwave is best. Break it up into small pieces and put in a Microwaveable bowl. Blast on full power at 30 second intervals, removing to stir between times. Do this a few times as possible until the chocolate is all melted, don't over do it as it will burn.
If the honeycomb is well risen, brittle and breaks easily under alittle pressure you've got it right, you shouldn't need to get the toffee hammer out for this, not should it be very chewy, a crunchy texture is what you're looking for.
Breaking honeycomb can create a lot of small pieces and crumbs. Don't waste these, either mixing into ice cream, or mix into left over melted chocolate and putting a large spoonful each into cake cases to make an alternative to rice crispy cakes.
We have a commercially produced chocolate bar in the Uk called a Crunchie, this chocolate honeycomb tastes exactly the same though the pieces are a little less regular in shape and size than the factories produce, adding to the fun.
These measurements are approximate, and the flavour can be altered by adding honey or glucose syrup, brown sugar or treacle instead of golden syrup, but don't overdo the sodium bicarb or that's all you'll taste, don't underdo it either or you'll get soft gooey toffee. (that's not too bad either!)
Make sure you use a deep tray, this stuff froths and takes on a life of it's own...you could end up with a candy coated kitchen that Hansel and Gretel would be proud of.