The Gibson is one of my all time favorite cocktails. This is my refined and slightly modified version.

60ml London Dry Gin, Tanqueray 20ml Dry Vermouth, Dolin Pinch of sea salt Cocktail onion

Dissolve small pinch of sea salt in gin, add vermouth, stir vigorously with ice. Pour in frosted glass, add cocktail onion and enjoy immediately.

The pinch of sea salt is not necessary but I find it adds just the right amount of salt combined with the sour onion (I prefer a brand like Mezzetta over the sweeter ones) and balances sweetness of the vermouth. But I also like salty cocktails.