By Zuza Zak
This is a very seasonal cocktail, because you need to gather the elderflowers when they are at their peak — white and fluffy, without any discolouration — in late spring. If you have no time for picking elderflowers, you could use shop-bought cordial instead, but the home-made stuff tastes a million times better.
For the elderflower syrup, put the elderflower heads into a stainless-steel pan with the sugar, lemon zest and water. Bring to the boil, stirring until the sugar dissolves, then turn down the heat and simmer for 15 minutes.
Strain through a sieve into a jug, pressing down with the back of a spoon to extract as much syrup as possible. Discard the elderflowers. Transfer the syrup to a 1 l