Fernet
Many people don’t know that fernet isn’t a product made by a single producer–Fratelli Branca–but a subcategory of amaro. It should be said, though, that its categorization as an amaro is sometimes disputed because many fernets are technically not liqueurs (contain no sugar except to color the spirit).
FERRARI
Mix equal parts (I do 1 to 1½ oz. each) Fernet-Branca or other fernet and Campari in a rocks glass. Add ice and stir for about 10 seconds. Garnish with an orange twist if you so wish.
ABV LEVEL
Though it is not a highly regulated category, there are throughlines across most fernets:
higher ABV than many amari (35-50; Branca sits at 40%)
low or no sugar
some combination of classical “fernet” botanicals, such as mint, eucalyptus, saffron, aloe ferox, Chinese rhubarb root, and myrrh; other botanicals are also used to distinguish various fernets from one another.
Though Branca is ubiquitous, you can also find the equally authentic Vittone brand, as well as North American examples like Fernet-Vallet (Mexico) and Letherbee Fernet (U.S.), among others.