
Creamy and crunchy, sweet and salty, this ice cream take caramel to new heights.
Grease an 8-inch square metal pan or cover the pan in foil and grease the foil.
Combine the water, golden syrup or honey and sugar in a medium-sized pot. Cook over medium heat until the sugar dissolves and the mixture becomes amber-colored. You can turn up the heat slightly once the sugar dissolves, but do not touch or stir the mixture!!!
Once the mixture is caramelized, take it off the heat and stir in the baking soda. Try to get the baking soda well incorporated without mixing too much, which bursts the air bubbles that make the honeycomb.

Immediately pour the mixture into the baking dish. Leave it alone in a cool place for hours, preferably overnight, until it is hard. Once it is fully cool, pry it out of the baking dish and break into pieces.

Beat the sugar and egg yolks together until they are a thick, pale yellow mixture.
Separately, slowly bring the milk to a low simmer. Add the hot milk to the sugar and egg mixture in a slow stream, whisking as you add. This process is called tempering and prevents the eggs from scrambling, which would happen if you added the hot milk all at once.
Pour the mixture back into the pot you used to heat the milk. Place the pot back over a low flame on the stovetop and heat to 160 degrees F., whisking constantly. Once the mixture is smooth and coats the back of a spoon, take it off the heat, transfer it to a small bowl and cover the top with plastic wrap, pressing the wrap against the top of the custard to prevent a skin from forming. Refrigerate (for several hours) until cool.

Whip the heavy cream until soft peaks form.

Fold the cream into the custard in a few batches, then churn in an ice cream maker according to the manufacturer's instructions.

Add the salted caramel sauce and the honeycomb candy once the ice cream is semi-solid, about 15 minutes into the churning process.

Once the honeycomb and salted caramel sauce are in and the ice cream is fully churned (to a soft serve consistency), transfer it to a freezer-proof container and freeze until solid.

As you can see from the photo, I didn't succeed in fully mixing the baking soda into the honeycomb. I was a bit gun shy because I didn't want to burst the air bubbles. I used a fork to mix and a whisk would probably do a better job.
It's easy to make homemade salted caramel sauce without a thermometer, but store-bought is fine too.
If you prefer to make this ice cream closer to the Murphys' version, use "regular" i.e. unsalted caramel sauce.
The instruction to bring custard to 160 degrees F is a food safety rule for pasteurizing the egg yolks. It's a somewhat different instruction than the Murphys provide in their recipe. Mine comes from the US Food & Drug Adminstration (FDA.) As an alternative to either method, use yolks from pasteurized eggs.
If your custard gets too hot and begins to scramble, take it off the heat, whisk it vigorously, and put it through a fine strainer. That should eliminate most or all of the lumps and bring it back to a smooth consistency.
The book points out that you can make this ice cream without a machine if you put the ice cream in a container in the freezer after adding the whipping cream to the custard base and then stir every few hours until it is solid, adding the honeycomb and caramel sauce once it is fairly solid.