1 1/2 ounces Angostura 18 year old rum
3/4-ounce orange liqueur (recommended: Cointreau)
1/4-ounce angostura bitters
2 ounces fresh lemon juice
1 teaspoon ground cinnamon
Fresh pineapple triangle, for garnish
Put all ingredients in a standard martini shaker. Fill shaker the rest of the way full with ice cubes. Cover and shake vigorously. Strain into a martini glass. Garnish with a trianglular piece of fresh pineapple.