Basil has a natural affinity to fruit and cream (well, broadly speaking, creamy, dairy-like flavors), a flavor trio that turns up in savory dishes left and right: basil with tomatoes and mozzarella, basil with pineapple and coconut milk, or basil with goat cheese and figs (or even basil with fruity olive oil and parm, as with homemade pesto).
But why should dinner have all the fun, when fruit with cream is already a classic formula for dessert?
That's where this emerald mousse comes in—as creamy and cool as ice cream, with all the complexity basil has to offer, tamed by sugar and cream in service of dessert, tied together with juicy bites of strawberry. Like my dark chocolate mousse, this recipe just so happens to be eggless. While that recipe is based on a cooked chocolate pudding, this one's more like a panna cotta lightened with whipped cream. Not exactly a traditional path to mousse, but a lot easier than whipping up separate bowls of egg yolks and whites and cream, plus it lets me break the recipe up into bite-sized chunks to tackle at a more leisurely pace.
I start by blooming a bit of gelatin in milk, and grinding my basil into a paste with a touch of sugar. This extracts tons of flavor and color without the need for any sort of lengthy steeping process (the same trick I use to make the basil ice cream from my book).
I dissolve the resulting paste (plus a pinch of salt) in a little milk over low heat, along with a secret ingredient: white chocolate. It's a convenient way to provide the mousse with additional sweetness, richness, and body. The fruity-floral aroma and mellow acidity of white chocolate, along with the added dose of dairy and cocoa butter, play right into basil's strength as a foil to fruit and cream.
As soon as the white chocolate has fully melted, I shut off the heat and stir in the bloomed gelatin until it is fully melted as well, then strain everything into a large bowl to remove the fibrous basil solids. Straining while still hot is important because, like over-brewed tea, the mousse has a tendency to get bitter when the basil leaves are left steeping for too long.
Finally, I dilute the concentrated base with cold milk, which speeds the cooling process along. From there, I cover and refrigerate the base until cold, all the way down to 40°F (4°C). This will take about three hours, but there's no harm in refrigerating the base up to 12 hours. From a food safety perspective, it's fine for up to a week, but the aroma of fresh basil will degrade over time, so don't stretch the process out too long. Overnight is one thing, if you're breaking up a recipe into manageable steps for a dinner party, but don't try to push it much longer than that.
Thanks to the gelatin and cocoa butter, the base will be comically thick once cold, but with some vigorous mixing with a spatula (or the paddle attachment of a stand mixer), it will turn smooth and creamy in no time, making it easy to fold in a bit of stiffly whipped cream*.
*If using a stand mixer, the beaten base can be scraped back into its original container, and the mixing bowl re-used to whip the cream; no need to clean it in between.
I start with about half the cream, folding briskly at first to loosen and homogenize the base. After that, I fold in the rest of the cream a little more gently, working until the mixture is nearly smooth. It's alright if a few lumps of whipped cream remain; the act of scraping the mousse into a disposable pastry bag, and piping it into cups, will take care of the rest. Besides, I'd rather have a few flecks of cream than a deflated mousse.
Once the portions are divvied up, cover each with plastic and refrigerate until set. This usually takes just an hour or so, but as with the previous refrigeration period, the timing needn't be exact. It's about balancing the minimum time needed for gelatin to set with convenience, while acknowledging that the clock will be ticking on freshness when that grace period is pushed too far.
My perfect timeline is to make the base after dinner, let it refrigerate overnight, then fold in the whipped cream before noon on the following day. That way the finished mousse will be fully set and ready to serve within a 24-hour window, freeing me up for whatever dinner preparations need to be made.
I like to serve the mousse with perfect summer strawberries, sliced and macerated with just enough sugar to draw out some juicy syrup. It's my absolute favorite pairing with basil, but apricots and nectarines are a close second, followed by tiny, farm-fresh raspberries or wild blackberries (sadly, their supermarket counterparts tend to be too sour and bland to do much for the basil, although in a pinch roasting can work wonders on crappy fruit).
A sprinkling of toasted pine nuts is a fitting element of crunch to pair with the basil, but slivered almonds or even a handful of granola will work well, too.
It's everything I want in a summer dessert, a celebration of seasonal produce that's cool, light, and refreshing, but rich enough to cut through the juicy brightness of fresh fruit.