When I first came to know of dessert using strawberry with vinegar years ago, I was stunned. Horrified. Petrified. Strawberry in vinegar, no way, I thought. The dessert I saw in a magazine was ice-cream with strawberries marinated in balsamic vinegar, and at that time I had never tasted balsamic vinegar, which wasn't common at all in Japan back in the day. It said balsamic vinegar isn't same as more "regular" vinegars we'd use, like rice or even apple vinegar but more fragrant and mellow kind. I couldn't help but wishing to try one, which I subsequently did.
Years after, I became a regular user of balsamic vinegar, mostly for cooking but sometimes in dessert as well. The easiest one was of course strawberries marinated in balsamic vinegar, but sometimes I'd boil down the vinegar and pour over ice-cream, a lot of times cherry or strawberry one. Balsamic vinegar is acid because it's vinegar after all, but when combined with fruits it seems to make a background flavor that enhances natural sweetness of the fruits.
I hadn't had any of such dessert for a while until recently when I had a pastry roll with freeze-dried strawberries, filled with custard flavored with balsamic vinegar. The bread was just okay, but it was good enough to make me feel like whipping up some dessert using the pair on my own.
And I brought myself to try and make strawberry mousse with balsamic vinegar. I wanted something very easy to make, and settled down with a recipe like this (in Japanese), one using strawberries, sugar and cream as the core ingredients, but not eggs.
At first I planned to make regular strawberry mousse and serve it with balsamic-marinated berries, but this recipe changed my mind; I decided to add the vinegar to the mousse, too, by marinating the berries before pureeing them.
Very dark, almost sepia-like balsamic vinegar turned the vivid red of strawberry into very dull brownish red, and for a moment I was worried that my mousse would look shabby. When added to the mousse base, to my surprise, the pureed berries tinted the mousse with pretty pink - not a happy bright pink but more subtle, nuanced pink. I liked it.
The mousse was extremely mellow and didn't quite taste of balsamic vinegar. You can tell there's something added to it, but might not figure it out. I served the mousse with diced strawberries tossed with balsamic vinegar on top, which added a more obvious balsamic flavor to the mousse and gave it a kick. I liked the mousse as it was, but I loved it with fresh berries and the little extra balsamic taste.