Start by making the lemon verbena cordial. Pour 350ml water into a saucepan and bring to a rolling boil. Add the lemon verbena and let steep for a few moments until the leaves have wilted a little, then add the caster sugar. Mix well until the sugar has dissolved. Turn the heat off and allow to cool. Once cool, transfer to a sealable container and place in the fridge for a minimum of 12hrs – or overnight. Then simply strain off and discard the leaves and bottle the cordial in a steralised bottle – it will keep for a week in the fridge.

To make the cocktail fill a wine glass two-thirds full with ice. Pour in the sherry, 25ml of the lemon verbena cordial and bitters and a splash of prosecco.

Stir to mix, adding a few more ice cubes and another dash of the prosecco. Finally, top with the remaining prosecco and give it a last mix before garnishing with a strip of lemon zest on a cocktail stick and a sprig of fresh mint.