The source treats an Old Fashioned as a framework for several coffee-led variations. Its examples move through smoked espresso, mocha, s'mores mocha, maple-brown-sugar and lemon versions. Each changes the relationship between the spirit, sweetness, bitters and coffee rather than creating an unrelated drink from scratch.
Choose one direction before combining additions. Chocolate and marshmallow produce a different impression from citrus bitters, while smoke introduces an aromatic element that can easily dominate. A coffee liqueur also changes the sweetness and composition compared with using espresso alone.
Measure the components and compare the drink as the ice melts. Keep the espresso recipe and syrup strength recorded if you want the result to be repeatable. These are interpretations of the source's cocktail ideas, not a claim of personal testing or a promise that adding more flavours always produces greater balance. The central task is keeping the chosen coffee contribution clear.
The conversation
A good question can make a better brew.