I think the coffee liqueur used is very important in driving the flavor - I used Borghetti and appreciated the earthy and mild bitter espresso with the rum notes, but it was a bit sweet and the port was hard to find. Maybe Mr. Black to dial back sweetness. Other comments suggest use of bitters - I think chocolate would fit nicely, and perhaps black walnut.

A decent cocktail - but I think it is a little tilted towards the cognac (not a spirit I favor). The fruit of the cognac and the maraschino are very nice, but they erase the port, and the rum notes are in the distant background.

A nice, nuanced cocktail that has traveled far from a Manhattan - but not exceptional.
A melange of flavors - the amaro (I used Averna) leads with a slightly sweet cola and licorice (among other spices & herbs) with mild bitterness following immediately. The spicy rye emerges in the mid, complemented by a *hint* of the dried fruit/raisin of the port, and the finish is dominated by the rye, with the Averna long gone. Smooth and full-bodied, but not syrupy, with some boozy heat emerging early and lasting into the finish.
I see others used black walnut bitters (an excellent suggestion!), and serving over ice to allow for some extended sipping and modest dilution - another great suggestion.

Delicious, but I like the Randy Sangaree better - there is more fruit and vanilla, and it isn't quite as boozy hot. That said, congratulations to the bartender ages ago who first came up with combining brandy and port - a combination that exceeds the sum of the parts!