Combine the aged rum, overproof rum, orange juice, lime juice, falernum and passion fruit syrup in a shaker.
Add a dash of Angostura and six drops of absinthe.
Add crushed ice and shake hard for 8 seconds.
Pour unstrained into a tiki mug or tall glass.
Top with crushed ice and garnish with a mint sprig and a lime wheel.
From Don the Beachcomber's Hollywood bar in the 1930s, recovered by Jeff Berry from the coded notebooks Don's bartenders used to keep the recipes secret. The absinthe is measured in drops for a reason.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Cobra's Fang.