Make the hokey pokey:

1. Line a baking tray with baking paper and set near the stove.
2. In a medium, heavy-based saucepan over medium heat, combine the sugar and golden syrup. Stir once to combine, then leave to cook without stirring until the mixture turns a deep golden amber, about 4–5 minutes. Keep a close eye on it — it can burn quickly.
3. Remove from heat immediately and quickly whisk in the baking soda. The mixture will foam and expand dramatically. Pour it straight onto the prepared tray — do not spread it. Leave it to cool and set completely, at least 30 minutes.
4. Once hard, break the honeycomb into small chunks. Store in an airtight container until needed (it will keep for a few days in a cool, dry place).

Make the custard ice cream base:

1. Put the milk and cream in a saucepan and heat until just below boiling. Meanwhile, whisk the sugar, egg yolks, and vanilla in a large bowl.
2. While whisking, slowly pour the hot milk mixture into the egg mixture until combined. Pour the custard back into the saucepan and cook over low heat, stirring constantly, until it thickens enough to just coat the back of a wooden spoon. Do not let it boil.
3. Cool the custard, then refrigerate for a couple of hours until well chilled.

Churn and freeze:

1. Churn the chilled custard in an ice cream maker according to the manufacturer’s instructions.
2. Once churned, fold in the hokey pokey chunks — do not add them while churning or they will be ground down and you will lose the crunch.
3. Scrape into a 1-litre freezer container, cover well, and freeze for several hours or overnight until solid.
4. Serve in cones or in dishes, drizzled with caramel or chocolate sauce if desired.