Add 50 grams cornflakes to a large jar. Pour 720ml milk over the cornflakes.

Seal the jar and shake well. Refrigerate overnight (or for at least 4 hours) to infuse.

Strain the cornflakes from the milk using a fine sieve, pressing firmly to extract as much milk as possible. You'll lose some volume to absorption. Set the strained cereal milk aside.

Preheat the oven to 120°C. Line a large baking tray with baking paper or a silicone mat.

Make the popcorn using your preferred method. Transfer to a large, deep bowl (it should only half fill the bowl to allow room for tossing). Add 50 grams cornflakes and mix together.

In a medium heavy-based pot, combine 150 grams butter, 200 grams sugar, and 2 tablespoons golden syrup. Bring to the boil over medium heat.

Continue to boil, stirring continuously, until the mixture turns golden brown and reaches 155°C on a sugar thermometer (hard crack stage).

Remove from heat and immediately stir in 1 teaspoon salt and 1/4 teaspoon bicarbonate of soda. The mixture will foam up. Stir vigorously for a few seconds.

Pour the hot caramel over the popcorn and cornflakes. Toss quickly to coat everything evenly.

Spread the caramel-covered mixture onto the prepared baking tray in an even layer.

Bake for 15 minutes. Remove from the oven and toss to ensure even coating. Return to the oven for a further 10 minutes.

Remove from the oven, toss once more, and leave to cool completely on the tray.

Once cool, break into clusters. Store in an airtight container.

Add the strained cereal milk and 6 scoops of vanilla ice cream to a blender. Blend until smooth and thick.

Pour the milkshake into a large glass, filling it about three-quarters full.

Add a few caramel corn and cornflake clusters into the milkshake, then top up with more milkshake.

Top with 2 more scoops of ice cream or pile on more caramel clusters. Serve immediately with a spoon and straw.