Bring mixture to a gentle simmer, stirring occasionally so the sugar dissolves. Simmer for 8–10 minutes until the guava softens and the liquid takes on a bright pink-orange color.

Remove from heat and let cool slightly, then mash the guava solids with the back of a spoon or a potato masher to release more juice and flavor (about 1–2 minutes).

Strain the mixture through a fine-mesh sieve into a bowl, pressing solids to extract as much liquid as possible. Discard solids or reserve for another use.

Stir in 1 tablespoon fresh lime juice while the syrup is still warm. Taste and, if you prefer a sweeter syrup, stir in up to 1 additional tablespoon sugar while warm until dissolved.

Cool the guava syrup to room temperature, then refrigerate until cold. Yields approximately 6–7 oz syrup.

Cocktail

Prepare glass

Fill a highball or Collins glass with ice to chill while you build the cocktail.

In a cocktail shaker, add 1.5 oz chilled guava syrup, 1.5 oz white rum, 0.5 oz fresh lime juice, 0.5 oz orange liqueur, and 1 oz cold pineapple juice.

Add a generous handful of ice to the shaker (about 1 cup). Shake vigorously for 10–12 seconds until the shaker feels cold.

Discard ice from the chilled glass. Strain the shaken mixture into the prepared glass over fresh ice (large cubes or crushed, per preference).

Top the drink with 1 oz club soda to give it sparkle and gently stir once to combine. If using, add 2 dashes Angostura bitters on top and gently swirl or drop into the drink for aroma and complexity.

Garnish with a lime wheel and a small guava slice or pineapple wedge and a mint sprig if desired.

Serve immediately.