When looking at matching food to wine there are a number of factors that need to be considered. With desserts the principle "rule" is that the wine should be sweeter than the dessert it is being paired with. If it isnt the end result is usually an unpleasant metallic taste on the palate. Creamy dishes need something with a reasonable amount of acidity to cleanse the fats off the palate. Other than that almost anything goes.
When im matching food and wine, I try to find flavours that complement each other. A classic example is chocolate and orange, a match for which Terry's chocolate companty have survived for decades. But there are many different types or grades of chocolate - milk, white, and varying degrees of dark with cocao contents varying from 30% to 80%. As well as this the sweetness of the chocolate varies with the darker higher cocao chocolates usually containing much less sugar than milk chocolate. So it all boils down to tasting combinations. The more bitter the chocolate the sweeter the wine can be to counterbalance the bitterness.
Currently we have a dessert on the gastro menu which is a dark chocolate collar with a bitter chocolate orange sorbet and caramelised orange sauce. Now you have two fairly bitter, unsweetened parts, with the caramel sauce providing the sweetener. So really the wine doesnt need to be megasweet. If im doing menu-matching with this then what I would do is offer two different glasses of wine per couple. The first is an Orange Muscat from a winemaker called Andrew Quady, who is based in Madera, California. Andrew used to be a pyrotechnician before turning his considerable talents to making wines. He only makes dessert wines, and some fortified port-style wines, which he calls Starboard. get it? Port - Starboard!! Anyway the wine is made from Muscat de Frontignon grape, and has a slightly orangey flavour which we know works well with chocolate. It is quite sweet, but so far the feedback has been good. The other wine that I serve is Boutielle Call from Bonny Doon Vineyards. This is a late harvest Syrah that is blended with Framboise made from three different raspberry breeds all grown in Washington State. Its a rich, unctious wine, with a fairly obvious raspberry flavour to it, which Im uncertain how it sits with the orangeyness of the dessert. The guests have been undecided with about 50% likey, 50% no likey. But its different, its unusual and if the raspberry wasnt so obvious I think it would work better. Which leads me to another wine that ought to work based on that conclusion.
Rosenblums Late Harvest Zinfandel - Rosie Rabbit vineyard. A rich deep red wine with a modicum of residual sugar. This goes really well with a chocolate fondant, or dark chocolate souffle.
Mas Amiel, Maury, a vin doux naturel from the Languedoc region of France is partially fermented Grenache that is then fortified with grape brandy to increase its alcoholic strength and halt the fermentation. The end result being that not all of the sugar has turned to alcohol, hence you have a sweet wine.
In a similar style a relatively young LBV port or port style wine would also work quite well. Weisse and Krohn do some great single colhieta aged tawnies in a multitude of vintages going back to the 50's. The 65 has a rich coffee/toffee'd nose that works well with heavy dark chocolate dishes - opera gateaux, sachertorte etc.
I havent really come across a good complement for white chocolate yet, but Im working on it!!