Put a handful of California grapes (any color works, but red are particularly striking) in a pint-size bar glass. Muddle for half a minute to break down the grapes, releasing their juices and separating the skins from the flesh a bit.
Add remaining ingredients, except for soda, to the glass. Add ice and top with a bar shaker and shake vigorously.
Pour into serving glass. Top with a splash of soda water. Skewer three or four California grapes and place on top of the glass as garnish.
Sponsor recipe courtesy of Zahra Bates, Mixologist at Providence in LA, for Grapes from California