Chill a double old-fashioned glass or a rocks glass by filling it with ice and set aside. Measure and have ready the dark rum, fresh lime juice, orgeat, pineapple juice, simple syrup and bitters.

Build and shake

Discard the ice from the chilled glass. In a cocktail shaker add 2 oz dark rum, 0.75 oz fresh lime juice, 0.5 oz orgeat, 1 oz fresh pineapple juice, 0.25 oz simple syrup, and 2 dashes Angostura bitters. Fill the shaker with ice (preferably cubed). Secure the lid and shake vigorously for 10–15 seconds until well chilled.

Prepare serving glass

Fill the chilled glass about three-quarters full with crushed ice (about 1 cup).

Strain and finish

Double-strain the shaken mixture over the crushed ice in the serving glass to remove small ice shards and any pulp. If you prefer a stronger rum aroma, float 0.25 oz (optional) additional dark rum on top by pouring it gently over the back of a spoon.

Garnish and serve

Garnish with a mint sprig and a lime wheel or wedge. Optionally grate a little nutmeg over the top for an aromatic finish. Serve with a short straw and enjoy immediately.