The Sunk Cost Mousse

I wish I could say that I first made this mousse as a little act of TLC, or to reward myself after a productive day. In truth, I threw it together around 10pm in my London flat - and halfway through, I was already regretting it.
This recipe dates back to just after COVID, in the early days of dating my now-husband. I had invited him over for dinner and although I wasn’t a bad cook by any means, I wasn’t used to cooking for other people. I decided on a simple risotto, my go-to at the time: inexpensive, relatively easy, and the kind of dish that suggests more kitchen prowess than it actually requires. I can’t remember if I also decided to serve a starter, but I do remember being stuck on dessert. I wanted something that didn’t need too many ingredients (and wouldn’t leave me with lots of leftovers). I love baking, but making a whole cake for just the two of us felt impractical, and I needed something that could be thrown together at the last minute.
Scouring the internet, I landed on BBC Good Food’s chocolate mousse*. I’ll admit, I’m not a huge chocolate dessert fan, but it felt like a safe bet. While not everyone loves chocolate in all its forms, very few tend to hate any of its variations.
So, I dashed out for ingredients and started prepping late at night - only to discover halfway through that my landlady didn’t own a whisk. Not an electric one, not even a hand one.
Which is how, if you’d been a fly on the wall, you’d have found me at 10pm furiously beating egg whites in a bowl with a fork. Even with Bridget Jones on TV to keep me company, it was the longest half hour of my life. But the blood, sweat, and (almost real) tears were worth it: on this occasion, the sunk cost fallacy worked in my favour.
A few notes on the recipe
As I mentioned, this recipe comes from BBC Good Food, though I’ve made a few small tweaks. See the recipe below*. This is one of the rare times I’ve written something specifically for two people. Whisking egg whites - for me at least - just isn’t worth it for a single mousse, so you may as well make two (or more, if you multiply the recipe). The portions are dainty though, so feel free to make just one hearty mousse for yourself (but stick with a single portion of nut butter, or it will be too cloying).
Since chocolate is the star ingredient, the mousse will only be as good as the chocolate you use. As Nigella Lawson always says, make sure it’s “good and dark.” Aim for the best dark chocolate you can afford - around 70% cocoa solids is ideal. Much higher, and the mousse loses its silky smoothness.
As for the nut butter, go for something smooth and good quality. I usually stick to 100% nut butters, though a little added salt or fat isn’t always a bad thing. Most varieties work - cashew, almond, pistachio - but I almost always reach for peanut butter. It’s cheaper, and chocolate + peanut is a classic pairing. If you like, throw on some chopped dry roasted nuts of the same type as your butter for a crunchy topping. Or, you might even want to add a sprinkling of flaked sea salt, if you like that combination.
Finally, the hands-on time is almost entirely down to how you whisk the egg whites. I don’t own an electric whisk, so I do it by hand, which takes a little longer. You could use a fork - but speaking from experience, that’s only worth it if the mousse is solely for you or if the person you’re serving it to is seriously committed to the relationship you share.