Substituting white chocolate in Julia Child's mousse
Guittard replied to my query after the fact, so I learned firsthand that one should use less liquid because cocoa solids in dark chocolate are absent from white chocolate.  I substituted 1/4 cup milk for the same amount of strong coffee in the original recipe, and the Baker's Premium White Chocolate liquefied.  Melted semisweet doesn't pour like it did, and I was paranoid my mousse wouldn't set.

I studied my liqueur options at the store.  A 750mL bottle of crème de cacao tempted me with thoughts of frozen cocktails, all requiring additional 750mL bottles of other liqueurs, and I didn't want to go there.  The selection of 50mL bottles was limited, but I settled on E&amp;J Vanilla brandy.

When I opened it, there was no essence of vanilla; I smelled only brandy.  The 1/4 teaspoon of vanilla extract I added to the milk was imperceptible, as well.  My attempt at white chocolate mousse was more like a brandy Alexander custard.  My official taster said he wouldn't have known I used either white chocolate or vanilla if I hadn't told him all about it.

His initial "Wow!" and the way he savored it conveyed his appreciation nonetheless.  Brandy made for a good flavoring.  If I found Baker's 4-ounce bars on sale again, I'd forgo using liquid in the melting step, and hope for a less custardy consistency.  I even reduced the butter by 2 tablespoons, and beat the living daylights out of it before folding in the egg whites.  It set, but a spoon won't stand up in it like the original.

Thank you for your advice:)