The muddling and the order of the ingredients helps ensure that all the flavors are well blended. Serve with a sugar cane swizzle stick or a wooden chopstick to keep the different flavors well blended.
Place the mint leaves in a highball glass and add the lime juice and sugars and gently muddle: press down on the mint leaves, lime juice, and sugars with a wooden spoon or muddler. Muddling releases the oils from the mint leaves. You don’t want shredded leaves floating around in the drink and getting stuck between your teeth—so muddle gently.
After muddling add crushed ice and rum, and top off with club soda. Garnish with a lime wedge and a mint sprig.
Feel free to substitute the sugar with 1 ounce of simple syrup.