Elderflower Lemonade

2 lemons
2 tbsp caster sugar
35ml elderflower cordial
1 handful of frozen berries
sparkling water, to top up

Squeeze the juice of one lemon into a jug, add the sugar and elderflower cordial and mix well to dissolve. Put a few ice cubes in each glass, slice the remaining lemon and add to the glasses along with the frozen berries. Top up with sparkling water to taste and mix with a straw.