On the trail of the perfect White Russian cocktail

My absolute favourite character ever from a movie is The Dude from The Big Lebowski! His ultimate drink, ordered wherever he goes, is a White Russian (Caucasian)…! I have made it a personal goal to find The Dude the best made one here in London. This quest has taken me from East to West and North to South but I still have not found the perfect cocktail… so I go on in search of the elusive White Russian!