Roughly chop the outer layer of a fennel bulb and some of the stalk until you have 1/2 cup chopped fennel. Place in a cocktail shaker. Add 1 ounce blanc vermouth, 1 1/2 ounces vodka, 1/4 ounce dry vermouth, 1/4 ounce absinthe, 1/2 ounce fresh lemon juice, and 1 teaspoon sugar. Shake vigorously until the liquid is cold and strain through a fine sieve into a highball glass filled with crushed ice. Top with 1 1/2 ounces club soda. Garnish with fennel fronds.
Recipe by Andrew Zerrip, head bartender at Olmsted in Brooklyn, New York.