Juice the lemons. Roll each lemon firmly on the countertop with the palm of your hand before cutting. This breaks the internal membranes and releases more juice. When you cut them in half, you should see the flesh glistening with moisture. Squeeze until you have 120ml of bright, tart juice. The colour should be a pale, translucent yellow with no seeds floating in it.

Combine the base. In a large jug, pour the rose syrup and the lemon juice together. Stir with a long spoon until they are fully blended. The mixture will turn a deep, rosy pink. Take a moment to smell it — the floral aroma of the rose should be clear and sweet, balanced by the sharp, clean scent of lemon.

Add the ice. Drop a generous handful of ice cubes into the jug. You should hear them clink against the glass. The ice will chill the drink quickly without diluting it too much, as long as you add the sparkling water next.

Pour the sparkling water. Slowly pour the chilled sparkling water into the jug. Watch as the pink liquid lightens to a soft, ballet-slipper shade. Tiny bubbles will race up from the bottom of the jug. Stir gently once or twice with the spoon — you want to combine the ingredients without knocking all the fizz out.

Taste and adjust. Dip a spoon into the jug and take a small sip. The flavour should be predominantly floral, with a bright, citrusy finish. If it tastes too sweet, add a squeeze more lemon juice. If it tastes too tart, stir in an extra tablespoon of rose syrup.

Pour and garnish. Divide the mocktail evenly between four glasses. Drop a lemon slice into each glass, letting it float on the surface. If you are using mint or raspberries, add them now. The mint should sit on top, releasing its fragrance as you drink. The raspberries will sink slowly, adding little pops of colour.