Make the brown sugar syrup. Place the brown sugar, water, cinnamon stick, and sea salt in a small saucepan. Set over a medium heat. Do not stir—let it sit. Watch for the surface to begin trembling, then bubbling. The smell is the first cue: it should shift from plain sweet to a deep, almost smoky caramel aroma. Let it boil gently for 3 minutes, until the liquid is the colour of dark amber and the bubbles are slow and thick. Remove from the heat and let it cool completely. The syrup will thicken as it rests, turning glossy and heavy like honey.

Prepare the coffee. Brew your espresso directly into a small heatproof jug or glass. The oil on the surface should be a dark, reddish-brown, and the crema should be a golden foam that holds for a moment when you tilt the cup. Set it aside to cool slightly—about 5 minutes. Hot coffee poured straight onto ice will melt it instantly, leaving you with a watery drink.

Chill your glasses. Pop two tall glasses into the freezer for 10 minutes. The frost that forms on the outside is a sign of success; it keeps your drink cold without diluting it.

Assemble the base. Spoon 2 tablespoons of the cooled brown sugar syrup into the bottom of each chilled glass. You will hear a satisfying, slow glug as it settles. Swirl the glass to coat the sides with a thin layer of syrup.

Add the ice. Fill each glass to the brim with ice cubes. Listen for the sharp clink against the glass. The ice should be packed tightly, leaving no gaps.

Pour the coffee. Divide the espresso evenly between the two glasses, pouring it directly over the ice. Watch the dark liquid snake through the ice, meeting the syrup at the bottom. The contrast of deep brown against clear ice is the visual cue that the layering has begun.

Froth the oat milk. Pour the chilled oat milk into a jar with a tight-fitting lid. Screw the lid on firmly and shake the jar as hard as you can for 20 seconds. You are looking for the milk to double in volume and become thick, with a layer of fine, stable foam on top. The sound changes from a slosh to a muffled, creamy thump when the froth is ready. Alternatively, use a handheld frother for 15 seconds until the milk is velvety and smooth.

Finish the pour. Slowly pour the frothed oat milk over the back of a spoon held just above the ice. This technique keeps the layers distinct. The milk will settle on top of the coffee, creating a pale, cloudy crown. Leave a small gap at the top of the glass for the final flourish.

Add the topping (optional). If using, dollop a spoonful of whipped cream on top. Drizzle a teaspoon of the remaining brown sugar syrup over the cream. The syrup will pool in little dark puddles on the white surface. My kids absolutely devour this every time I make it, and they always insist on this extra sweet layer.