In cocktail shaker, or in tall glass, add mint leaves and sugar. Using a wooden pestle, muddle mint with sugar until mint is bruised.
Add nectar, lemon juice, club soda and rum, if desired. Shake until combined.
Evenly divide guava mojito into two tall glasses with ice. Serve immediately.
If you’re whipping up a batch of mojitos and your wooden pestle is missing in action, don’t panic! Instead, use your wooden spoon to muddle the mint. To do, flip the spoon and use the blunt end to firmly press the mint into the sugar until the herb turns dark green and releases its essential oils and fragrance.