I thought I had a great idea. Does anyone remember back when I made lemon curd? Turns out you can make orange curd the same way. Just use orange zest instead of lemon, and replace about 2/3 of the lemon juice with orange juice.
Making all that buttercream for the Tux cake left me with a lot of egg yolks. What do I do when I have leftover egg yolks? I make orange curd. I was armed with an industrial supply of orange curd, and I had no idea what to do with it all. So I decided to try making an orange mousse.
Now, let's get the basics of mousse straight. As we all know from our high school French class (don't worry, I didn't bother taking it either), the word mousse means 'froth' or 'foam'? So the first requirement of a mousse is froth or foam, right? Well, something like that. There's actually two main types of mousse: cream-based, and egg white-based. Either one of them can be whipped into a kind of foam, but with strangely different requirements. Cream needs to contain at least 36% butterfat, or else it doesn't really whip up. It also whips up better when it's cold. Egg whites whip up better when they're warm, and if there's even a speck of fat, they won't whip. Period.
The second requirement for mousse is smoothness. It needs to be perfectly smooth. Smooth, I say! Let's say you like chocolate. Who doesn't? And let's say you like sprinkling chopped almonds or something into your chocolate. It might taste good when you mix it into your chocolate mousse, but it's not really mousse anymore, right? Because it's not smooth. Mousse needs to be smooth.
Now, chocolate mousse is pretty easy stuff. I've always based mine off of Alton Brown's recipe, but I go a little simpler. I melt a little chocolate, and while it's cooling I whip up an equal weight of heavy cream, which I then fold into the cooling chocolate. It's an easy recipe. It's a recipe that I thought might work well with orange curd instead of chocolate. It would be like a orange creamsicle, but creamier and without a stick.
I put some orange curd in a bowl and whipped up an equal weight of cream in a different bowl. I folded them together and loaded the mixture into a piping bag with a star tip. I pulled out a martini glass, piped the orange mousse into it, and dropped a few pieces of crystalized ginger on top of it.
It looked okay but it was a little, well, loose. As opposed to stiff. Chocolate mousse can be refrigerated for a day or two, but I think this would have fallen into a puddle within a few hours. What went wrong? Then I realized my mistake. When chocolate cools, it hardens. If you cool a pound or two of chocolate, without anything mixed into it, you end up with a brick. When you cool curd, it remains soft and spreadable.
Just for the heck of it, I tossed the bowl into the freezer, and gave it a gentle stir (kind of like folding it) every half hour or so. After a couple of hours, I had what was basically ice cream. Really, really rich ice cream. In fact, thinking about it, I realized that egg-based ice cream is basically just a stirred custard (like curd) with a bunch of milk stirred into it. Mine was kind of like the same thing, but with a lot of butter added.
It tasted pretty good, maybe even a little better than in mousse form. Just like a super, super, super premium ice cream. Unfortunately, it was a little too super premium, by which I mean it had a lot of a fatty feeling on the tongue. It was just a little too much. In fact, the sugary crystalized ginger that I also added to it actually cut through the fat a little bit.
It was an eye-opening couple of experiments. I'm definitely going to have to play with mousses and stirred custards a little more in the future, but maybe not at the same time.