The Chicago Tribune has an article focusing on amari as an ingredient, and even presents the Shift Drink, an homage to West Coast bartenders' favorite amaro. The article adapts it for any amaro, so here's the original, using Fernet:

Shift Drink

• 1.5 oz rye whiskey
• 0.75 oz Domaine de Canton
• 0.5 oz Fernet-Branca
• 0.75 oz lemon juice

Shake over ice, strain, garnish with lemon twist