Add ingredients to an ice-filled shaker and have at it for 20 seconds or so.
Strain into a chilled cocktail glass, no garnish.
Amaro Nonino can be tricky to find. Amaro Montegro works and makes the drink a little more bitter, still tasty. Some friends have had success with Amaro Lucano, but felt it was a different drink. There are a lot of amari out there.