Fill a tall glass with crushed ice.
Combine the white rum, cognac, gin, orange juice, lemon juice and orgeat in a shaker.
Add ice and shake hard for 10 seconds.
Strain into the prepared glass and top with more crushed ice.
Float the sherry gently over the surface and garnish with a mint sprig.
Victor Bergeron's creation for Trader Vic's, and his own printed advice was that after two of them you could not see through the fog. The sherry float is not a garnish: it is the ingredient that makes the drink taste finished.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Fog Cutter.