I found this while looking around for something low booze to make on an exceedingly hot summer afternoon in New Orleans. It's credited to David Slape, formerly of Del Posto and PDT in NYC. I'm looking forward to trying different variations to attempt to make a dent in the bottle of Carpano Antica Formula sitting in my fridge.
1.5 oz. Carpano Antica Formula Vermouth
.5 oz. Campari
.75 oz. fresh lemon juice
.75 oz. fresh lime juice
.75 oz. fresh orange juice
.5 oz. simple syrup
Shake ingredients over ice and strain into a rocks glass over fresh ice. Garnish with an orange twist.