Make the Raspberry Syrup: Combine the 300g raspberries, 200g caster sugar, and 250ml water in a medium saucepan. Set it over a medium heat and stir gently with a wooden spoon. You will see the sugar dissolving, and the liquid will turn a deep, cloudy crimson as the berries begin to break down. Bring it to a gentle simmer, not a rolling boil — you want small, lazy bubbles around the edge of the pan. Let it simmer for 5 minutes, until the raspberries have completely collapsed and the syrup has thickened slightly, coating the back of a spoon.

Strain the Syrup: Place a fine-mesh sieve over a heatproof bowl or jug. Pour the hot raspberry mixture through the sieve, pressing down on the solids with the back of a spoon to extract every last drop of that jewel-toned liquid. You should be left with a clear, vibrant syrup and a small amount of dry, pale seeds in the sieve. Discard the seeds and allow the syrup to cool completely to room temperature. The aroma at this stage is intensely fruity and sweet.

Prepare the Lemon Base: While the syrup cools, juice your lemons. Roll the lemons firmly on the countertop under your palm before cutting — this releases the juices and yields more liquid. You need 200ml of juice. Strain the juice through a small sieve to remove any pips and pulp, giving you a smooth, bright-yellow liquid with a sharp, zesty scent. Set this aside.

Chill Everything: For the best result, the syrup, lemon juice, and sparkling water must be thoroughly chilled. Place the syrup in the refrigerator for at least 1 hour. You can also chill the serving glasses at the same time — a frosty glass is a small touch that makes a noticeable difference.

Assemble the Drinks: For each glass, pour 2 tablespoons (30ml) of the chilled raspberry syrup and 1 tablespoon (15ml) of the lemon juice into the bottom. The syrup will pool heavily at the bottom, creating a dark, concentrated layer. Add a handful of ice cubes — the sound of the ice hitting the glass is a satisfying, crisp clink.

Top with Sparkling Water: Slowly pour 150ml of the chilled sparkling water into each glass, tilting the glass slightly to preserve the fizz. Watch as the carbonation immediately lifts the heavy syrup, creating dramatic, swirling ribbons of ruby red that bleed upwards into the clear water. The effervescence releases a burst of raspberry and lemon aromas into the air.

Garnish and Serve: Gently stir the drink once with a long spoon to marry the layers, leaving a gradient of colour from deep red at the bottom to pale pink at the top. Garnish each glass with a sprig of fresh mint, a thin slice of lemon, and two or three whole fresh raspberries. The final visual is a study in contrasts: the vibrant crimson liquid, the glossy green mint, and the translucent yellow of the lemon slice.