Vesper Americano

Most reasonable recipes for this cocktail add up to 3 ounces, but this is The Forbidden Patio. So here's 4 ounces.

2oz London Dry Gin
1oz Vodka
1oz Cocchi Americano
1 Dash Bittermen's Hopped Grapefruit Bitters

Stir ingredients together over ice. Strain into a chilled martini glass. Garnish with a citrus peel.