Honeycomb Boulders

Is anyone else familiar with the Cadbury Crunchie bar? It’s awesome! It has an amazingly crunchy and sweet honeycomb toffee center covered in chocolate. I used to eat at least two bars at any one time, most of the time making my tongue sore from the sharp sugary edges. Sadly, it’s no longer available in the Philippine market.

One of my favorite candy bars

One of my favorite candy bars

Fortunately last Christmas break I had plenty of time to experiment in the kitchen, so I thought, “Why not try making my own honeycomb confection?” I’ve made brittle before, and I know that the honeycomb toffee is similarly made from caramel, but how does one get it to that airy consistency?

I researched a bit on that and learned that the key is baking soda, an item that’s cheap and easy to get if you don’t already have it at home. I’d like to take a bit of time to discuss how it works. NERD ALERT!!!

Baking soda is basically sodium bicarbonate (NaHCO3), and the interesting thing that it does is to “decompose” at temperatures higher than 100°C (boiling point of water) or even lower if it is dissolved in water. No, “decompose” doesn’t mean that nasty rotting thing food does when kept too long—it means that the sodium bicarbonate breaks down into other materials as it heats, specifically, into carbon dioxide gas, water vapor and sodium carbonate. As you may have figured out, it’s the carbon dioxide gas that fluffs up baked food items, like in cakes, or when it is produced during bread dough fermentation with yeast. In slightly acidic batters like in a red velvet cake batter, the acidity reacts with the baking soda, producing carbon dioxide at a much faster rate than by simply heating it during baking. That’s why a vinegar-baking soda mixture is great for volcano science experiments. 🙂

For those of you who want to know what the reaction is

For those of you who want to know what the reaction is

When making sugar confections, you work with temperatures between 250°F to 350°F (121°C to 177°C), which, hey, are higher than the 100°C point at which baking soda decomposes. And that’s what we’re going to take advantage of to make the honeycomb toffee.


Sugar + Honey + Baking Soda = Honeycomb Toffee!


  • 3 cups sugar
  • 1/2 cup honey
  • 1/2 cup water
  • 2 tablespoons baking soda
  • dark chocolate, chopped into small pieces (at least 250 grams)
  • 1/2 cup butter


Lightly grease a 12″ x 9″ deep-rimmed baking pan.


Wet the sugar with water and honey before heating

In a medium saucepan (with high sides) over medium heat, combine the sugar, honey and water. Stir through to wet the sugar then leave to cook. Do not stir the mixture as it cooks. Brush the sides of the pan with water occasionally to dissolve any crystallized sugar. From time to time, move the pan around to swirl the sugar as it cooks. Using a candy thermometer, regularly check the temperature.


Be careful–it’s really hot

Once the sugar cooks to 300°F (150°C, the hard crack stage), immediately remove from heat and quickly whisk in the baking soda. The mixture will froth, but don’t wait for it to finish frothing—10 seconds of whisking should do. Carefully transfer the caramel into the greased baking pan, allowing it to spread on its own. You will notice that it will keep on growing and frothing. Leave to cool for at least 2 hours.


I may have over-filled…

Once cooled and hardened, remove the toffee from the pan and break or chop into 2-inch blocks. It doesn’t have to be exact as the toffee is brittle and has a tendency to break irregularly.

In a microwaveable bowl, combine the dark chocolate and the butter. Cook in the microwave on high for 1 minute. Stir through, but don’t expect the chocolate to be completely melted at this point. Repeat the cooking process for another minute, then stir through. Usually doing this 3 times is enough. Alternatively, the chocolate and butter may be melted over a double boiler.


Cover in chocolate over a wire rack

Place a small wire rack over a baking sheet. Place blocks of the toffee on the wire rack at least two inches apart from one another. Spoon over some melted chocolate to cover the honeycomb. Once covered, put them in the fridge for at least 5 minutes for the chocolate to set. Remove from the fridge and turn over the honeycomb to expose the side that’s not yet covered by chocolate. Spoon over some more chocolate to completely cover the honeycomb. Again, put them in the fridge to set. Any chocolate that drips into the baking sheet may be remelted so no chocolate is wasted.

Keep the finished honeycomb boulders in an airtight container. Eat within a week.

You may have noticed from my photos that the pan I used was only 9″ x 9″. It was small for this batch of honeycomb toffee, so I adjusted my recommended pan size. I also used a silicon pan because I didn’t want to bother with greasing a normal pan, and also because I can just peel the pan off my toffee afterwards. Another alternative would be to use baking parchment to line a pan. I poured the excess toffee over baking parchment and found that it can be easily removed once set.


Enjoy the sugar rush!

Making these took a bit of effort, at least for someone like me, but the results were worth the effort. Try these out and leave a comment below on how it goes for you. 🙂


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