2-3oz. Light rum
1oz. Lime juice (one lime, essentially)
2 tsp. Sugar
2-4 Mint sprigs
Muddle the mint and sugar with a splash of soda water in bottom of a mixing glass until sugar dissolves and you can smell the mint. Squeeze the lime into the glass, add rum, and shake with ice. Strain over cracked ice in a highball glass. Top with soda water, garnish with mint sprig and serve.
I’ve also done this by placing the mint leaves in the bottom of the glass you’ll serve it in and muddling it with the sugar there. Then the mint stays in the drink. Of course, this depends on the type of glass you use.