For the Fernet Branca Ice Cream:
In a large bowl, combine cocoa powder, chocolate, and Fernet Branca. In a pot, combine milk, cream, sugar, and cocoa butter. Heat over medium to a near simmer and pour over cocoa mixture, whisking to a smooth consistency. Refrigerate overnight. Process in an ice cream machine according to the manufacturer’s instructions.
For the Fernet for All:
In a mixing glass, combine the rye, crème de cacao, and Fernet. Add ice and stir for 10 seconds. Strain into a cocktail glass. Garnish with mint.
To Assemble and Serve:
Spoon a quenelle of Fernet Branca Ice Cream into a small bowl and set on a tray. Next to the ice cream, set the Fernet for All. Pour Jelinek Fernet into a mug and place next to the cocktail.