Add mint and simple syrup to a highball glass.

Grab the muddler from your cocktail set and lightly muddle mint and sweetener, being careful not to completely crush or pulverize the mint. You want to think of this as gently massaging the minty aroma and oils out of the leaves.

Add white rum and lime juice. Stir until mixed.

Add ice. Pour club soda over ice to the top of the glass. Give it a gentle stir to mix. Use a spoon to scoop/stir some of the mint towards the middle and top of the drink.

Optionally, add a splash of bitters.

Garnish with mint sprig and lime wheel. Add a straw, then sip and enjoy!