Pour the gin and one sprig rosemary to the glass. Crush lightly using a muddler to infuse the flavour of the rosemary. Remove the rosemary sprig after muddling.
Add a few ice cubes and fill the glass with the tonic water.
Garnish and serve with a sprig of rosemary and lemon slice.
Notes
(Best served in a Collins glass or Stemless wine glass)