A Gotham Cocktail combines cognac, dry vermouth, creme de cassis and lemon juice with a lemon twist for garnish. I got the recipe from Gary Regan's The Joy of Mixology when my wife asked for something with lemon juice. Regan got it from David Wondrich who invented it for the debut of Gotham magazine, thus the name. Any Batman associations are coincidental.
The drink is definitely on the sweeter side. I would describe the flavor as dark raisiny, probably thanks mostly to the cassis. There's a slight smokiness, too, perhaps from the vermouth. There actually isn't much of the lemon juice - only two dashes. Not sure that's enough to supply much. It might be interesting to try the same mixture without the lemon side by side with Wondrich's original.