(Or, rather, no-churn potentially non-dairy frozen custard. Close enough)
tldr: pastry cream + swiss meringue + cold. Freeze and enjoy!
I occasionally get an urge to make ice cream, but to date it’s never been strong enough to bother buying an ice cream machine — I’ve had those in the past and they’re frankly too much hassle for the utility, especially when I have a J.P. Licks within reasonable walking distance. Still, the idea of a no-churn ice cream is tempting, and I was wondering what I could do to make some when I wanted. Sure, there’s semifreddo which is a good enough option, but that requires having heavy cream around and I often don’t.
Thinking about ice cream got me thinking about one of its relatives, frozen custard (which is awesome), and that got me thinking that custard is almost pastry cream, which I do a bunch, pastry cream is easy and also potentially non-dairy, and I pretty much always have the ingredients around.
Just making and freezing pastry cream isn’t great because it’s kinda solid (turns out that all that air churned into ice cream really is important) so you need air in there. Whipped cream is useful for this but, as previously noted, I don’t usually have cream around for whipping.
My first thought was that pastry cream maybe could be whipped enough, but nope. It’s not like ganache where you can get a lot of air in, which isn’t surprising. (Fine, maybe with a lot of corn starch or added fat, but not base pastry cream) But… one of the things left over from pastry cream making is egg white, and with egg whites you can make meringue. Which is mostly air and traditionally used as a lightener for things. Turns out that if you make a batch of pastry cream then make a batch of Swiss meringue with the leftover whites and mix it in that you get a really rich, luscious, tasty frozen dessert. Score!
three egg yolks (50g(ish), but whatever, close enough)
20g corn starch
(optional) splash of flavoring like vanilla
Toss everything into a pot. Stirring the whole damn time, because burnt pastry cream is awful, you bring this to a sputtering boil and cook or two minutes. (you really need to just make sure everything hits 75c/170f to neutralize the starch-munching enzymes in the egg yolks, though freezing makes all this much more forgiving)
Pop this into something that will let it cool quickly (I use a cake pan), cover with some plastic wrap or something so you don’t get a skin, and cool. Fridge-cool is best, but room temperature is tolerable.
While that’s cooling make the meringue which is stupid easy:
three egg whites
25g sugar (two tablespoons)
2g cream of tartar (optional)
Mix these in a metal bowl and heat over a bain marie until it hits 71c/160f. Take off the heat and whip to soft peaks.
When the pastry cream is cool-ish, whip it up as best you can (which won’t be great but give it a go for 30 seconds or so), fold in the egg whites and stir to combine. Put some plastic wrap on top for skin-prevention safety, drop everything into the freezer, and freeze until it’s solid.
Now, traditionally pastry cream is made with milk but it’s 100% fine to substitute any kind of liquid. Want orange “ice cream”? Use OJ. Want lemon? Use lemon juice. (I’d add a bit more sugar, and a couple of grams of baking soda to cut the acid, but you do you) Want Bailey’s Irish Cream flavor? You’d fit in well with a bunch of lawyers I know and also that’s probably awesome. (Might want to set your freezer a little colder for that) Anyway, choose your liquid, and if it’s not milk based then this is dairy free for a bonus.
Anyway, there you go. Pastry cream + swiss meringue, mix, freeze.
It does have a bit of a cooked flavor because, well, it is. Since it’s frozen you can probably get away with just heating it up until it gets thick rather than fully cooking it — I suspect (though I haven’t checked) that it will freeze up well before the amylases in the egg yolks liquefy the starches and turn it to goo.
As a bonus it’s even kinda lower-fat/lower-calorie than actual ice cream — there’s relatively little fat in the pastry cream itself, and none in the meringue. (That’s kind of beside the point, though.)