1 1/2 ounces gin
1 ounce Cointreau
1/2 ounce Campari
3/4 ounce lemon juice
Garnish: Lemon twist
Shake with ice. Strain into a cocktail glass.
Source: Paul Harrington

This is a wonderful recipe created by Paul Harrington in the 1990's while working in San Francisco. I've slightly changed the ratios of his original version for the one I use. If you'd like to try Paul's original recipe, it was 1 1/2 oz gin, 1/4 oz Cointreau, 1/4 oz Campari, and 3/4 oz lemon juice.