+1 on the El Diablo for cassis. I also like it as a substitute for blackberry liqueur in a Gin Bramble, as well as in the CEO from Joy of Mixology, and Jamie Boudreau's "Angel's Share": 1.5 oz. Bourbon, 0.5 oz. Ramazzotti amaro, 0.25 oz. cassis, dash of Fee Brothers orange bitters. Stir, strain, lemon twist.
Amaretto is good as an amaretto sour and in a Godfather.
Cherry brandy is good in Singapore Slings and Blood & Sand.
Apricot brandy is good in a number of things. (I learned the other night that the Millionaire is not one of them.) One of my favourites is the Stone Fruit Sour
. Barnum (Was Right) is a good one, too, and there are a bunch of options in Joy of Mixology. It also makes a good sweetener in a Tom Collins variation, though better with lime juice than lemon.
To date, I have not found a good application for limoncello in cocktails, though I haven't tried really hard. I know eje uses it as a substitute for sirop de citron in some of the old cocktails that call for that with kola tonic.
Edited by mkayahara, 26 July 2011 - 06:42 PM.