Bourbon, Sweet vermouth, Aperol, Suze, Grapefruit bitters, Grapefruit peel
Long stir & strain into soda siphon or cream whipper*. Carbonate**. Serve up in glass of choice. Garnish.
* If using a Perlini or similar: shake w/ ice before & after charging.
** Charge with CO2, shake 15-30 seconds, let rest 30 seconds. For best results, charge twice, shake, and refrigerate for at least 30 minutes.