Test oil - Heat oil in a large pot over medium heat. Add a few pieces of popcorn and wait until it pops, then quickly remove.

Pop - Add remaining popcorn, elevate off stove to shake and spread corn out evenly. Cover with a lid. Once the popcorn starts popping in earnest, shake the pot gently once. Then crack the lid a tiny bit - let's steam escape for crisper popcorn.

Remove from heat when the popping stops (when you can count to 3 between pops) and transfer to a (very!) large bowl.

Preheat oven to 110°C/230°F (both fan and standard ovens).

Combine - Melt butter in a saucepan over medium heat. Add sugar, corn syrup and salt. Stir until just combined.

Simmer - When it starts to bubble, simmer for 4 minutes - DO NOT STIR!

Baking soda "foamy" - Remove from heat then quickly whisk in caramel (toffee or vanilla) and baking soda. When you stop whisking, the caramel will foam and increase in volume.

Coat popcorn - Quickly pour straight over popcorn, toss until caramel cools and starts to harden.

Spread popcorn on 2 large paper lined baking trays.

Bake for 45 minutes, tossing every 10 minutes or so. Caramel will remelt for the first 2-3 tosses - tossing coats popcorn more evenly with caramel. (If using glucose, bake further 15 minutes).

Cool - Remove from oven, leave to cool on the tray for 20 minutes. Then break up the popcorn - no need to be too pedantic, clumps are great!

Crumbs - Place biscuits in a ziplock bag and bash into crumbs.

Melt chocolate - Place chocolate in a heatproof bowl and microwave in 30 second increments on high, stirring in between, until melted and smooth - about 1 1/2 minutes. (If doing a small amount of white chocolate, reduce to 20 second increments).

Piping bags - Transfer chocolate into a piping bag. Use scissors to snip a small opening at the tip. (Alternative: just drizzle with a spoon).

Drizzle & crumb - Push the popcorn together but in a single layer. Drizzle criss-cross (or any pattern!) all over the popcorn. Sprinkle with biscuits crumbs while the chocolate is wet so it sticks.

Fridge - Refrigerate for 15 minutes until the chocolate is firm. Gently break popcorn into pieces. EAT!

Store in an airtight container in a cool place. Stays crisp for at least a week. Our test batches never lasted any longer!