Step 1

In a sturdy, heavy-bottomed, tall cocktail glass, add the sugar and 3 sprigs of the mint (we’ll reserve the last sprig for garnish).

Step 2

Muddle the mint with the sugar about 5 to 10 times, until the mint is very fragrant (not so much that the mint completely falls apart).

Step 3

Pour in the rum and the lime juice, and gently stir a few times to help dissolve the sugar. Fill the glass with ice.

Step 4

Fill the glass with club soda nearly to the top. Gently stir in a circular motion to combine, then use your spoon to drag some of the muddled mint higher up into the glass.

Step 5

Taste, and stir in more sugar if desired. Add a drop or two of bitters, if desired.

Step 6

To garnish, place the lime round in the glass. Gently clap the remaining sprig of mint between your palms (this releases some of the oils) and tuck it into your glass, leaving the top exposed. Serve cold, with a wide straw.