Passion Fruit Mai Tai

Halve passion fruit crosswise, if using. Press flesh through a sieve set over a small bowl to extract juice; discard solids.

Combine passion fruit, pineapple, orange, and lime juices in a cocktail shaker. Add rums and orange liqueur, and shake well. Fill two 16-ounce highball glasses halfway with crushed ice; strain juice mixture into glasses, dividing evenly. Garnish with a pineapple slice, if desired.