In a sturdy mixing glass or the serving highball, add the fresh blackberries, fresh mint leaves, and simple syrup (0.5 oz). Using a muddler, gently muddle 6 blackberries and the mint leaves just enough to release the blackberry juices and mint oils — about 6–8 gentle presses. Avoid over-muddling the mint to prevent bitterness.

Add spirits and citrus

Add 2 oz Bacardi Superior rum and 1 oz fresh lime juice to the muddled mixture. If you prefer a stronger blackberry presence, add 0.5 oz blackberry puree at this stage.

Shake (optional) and add ice

If using a cocktail shaker: add a few ice cubes to the shaker, transfer the muddled mixture into it, and shake briefly (6–8 seconds) to chill and combine. If building in the glass: fill the serving glass with crushed ice (about 1 cup) and stir the mixture gently to combine and chill.

Top with soda

Pour the cocktail into a highball or Collins glass (if shaken, strain into the glass over crushed ice). Top with approximately 3 oz club soda, gently fold/stir once to integrate without losing carbonation.

Garnish and finish

Garnish with a fresh mint sprig and a lime wheel or wedge. Optionally, float an additional whole blackberry on top for presentation. Serve with a straw and a small stirring stick.

Notes

Adjust sweetness by increasing or decreasing simple syrup to taste. To make the cocktail batch-ready, triple ingredients and combine in a pitcher, adding soda just before serving.