Jeff Grdinich created the 60/40 at the New Orleans Tales of the Cocktail festival with the last two ingredients available after everything else had run out: St-Germain elderflower liqueur and Averna amaro.
In a jar, combine the amaro and elderflower liqueur and stir well. Cover and refrigerate for at least 1 hour and up to 1 month. Pour into ice-filled rocks glasses.
