By now, you probably know that I’m all about the buttery frostings. That’s why I’ve posted so many recipes for them (like this butter frosting with an orangey variation, a marshmallow fluff frosting, this one with toasted pecans; and many more).
But sometimes I want to top my low-carb cakes and cupcakes with a frosting that’s slightly less buttery, but still rich and delicious. So I developed this super-velvety vanilla-flavored sugar-free frosting. It’s a tad lighter than regular buttercream frosting but still outstandingly rich. And it’s perfect for piping; just wait till you see these photos (and I’m not even a professional confectioner, I swear!)
Tips for making The Very Best Sugar-Free Vanilla Frosting
Although it only calls for a few ingredients, you’ll need a little bit more time to prepare this frosting. In many of my previous frosting recipes, you just mix all the ingredients together and that’s it. This recipe takes a little more effort, but believe me, it’s more than worth it!
So, the key to this frosting is a vanilla custard that works as a velvety base. The custard is really easy to make: You just mix all the custard ingredients together and heat over a low heat until thick. Easy as pie — or should I say custard?
Beating the softened butter (softened = at room temperature) until fluffy and pale before you add the custard is another key to ensuring that this frosting is really light.
Then you just add the custard and the rest of the ingredients and beat again until fluffy. Done!
Actually, it doesn’t matter if you add the vanilla extract and the salt to the butter before beating it or after — you might notice that I’ve mixed up things a little in the video and don’t add the ingredients in the same order than in the recipe. It doesn’t matter; the result is the same.
When you make the custard, it’s important to use a low enough temperature and to mix constantly, scraping the bottom of the saucepan all the time, so that the mixture doesn’t get lumpy.
One more tip, though: let the custard cool down to room temperature and no colder. When you add it to the butter, the mixture will form nasty lumps if the custard is too cold! You can place the custard in the fridge for half an hour or so for faster cooling, but don’t leave it there for any longer.
Other than that, this fantastic frosting is surprisingly easy to make. Here’s how:
First, make the custard. Place the cream…
…erythritol…
…and the egg yolks into a small saucepan.
Heat over a low heat, constantly mixing…
…until the mixture thickens. Don’t let it boil!
Let the custard cool down to room temperature.
When the custard is cool, beat the butter…
…until fluffy and pale, about five minutes.
Add the vanilla extract…
…the salt (if using)…
…and the custard.
Beat until fluffy…
…about one to two minutes.
Use immediately as filling or frosting. Yum!
My sugar-free frosting experiments
I’ve done plenty of sugar-free frosting experiments over the years, but I did the most recent ones a couple of months ago. I actually wasn’t aiming at anything specific; I just wanted to try out different types of frostings, mainly for frosting low-carb cakes. You know, my long-time dream has been to start a blog featuring more sophisticated recipes—something outstanding, like healthy party recipes. I’ve done lots of awesome recipes along these lines and would really like to publish them!
However, I’ve been low on just one essential ingredient: time. That’s because I’ve had a ton of other projects on my plate (like studying nutrition therapy, meeting clients, writing books, doing language technology projects, and simply taking care of my family). I’ve also become a specialist on the vegan keto diet; in fact, I was just interviewed for a podcast a couple of days ago. That also included a 7-day meal plan (in Finnish) which I’m going to translate into English as soon as I can.
Of course, I still want to make you happy by posting easy 5-ingredient recipes on this blog, just like I’ve done for over six years now. I just love developing recipes in general, and if you like them, too, I’m even happier!
So, like I said, a couple of months ago, I got stuck into lots of different types of sugar-free frosting and icing experiments, from stiff and buttery to lighter, more delicate varieties. And I came up with a really sticky one which worked well as an icing for donuts. (My son loved to spread it on top of his crackers, too!)
I was especially delighted with a slightly lighter version of the traditional buttercream frosting. Although I love butter, for a change I do like a frosting that’s a little on the lighter side but still pleasantly buttery. When I got the idea to use vanilla custard as a base before adding the butter, things improved dramatically and the frosting turned out to be just what I’d been looking for.
And I actually used this frosting as filling in my bébé pastries, because it reminded me so much of the filling in those childhood-favorite pastries. I’m pretty sure they’re a traditional Finnish thing; the shortcrust pastries are filled with a light, fluffy, buttery filling, and are usually glazed with a sugary pink glaze (though different versions – like mocha with a brown glaze – do exist). However, nowadays the regular version is full of sugars, syrups, hydrogenated vegetable fats, colorings, food additives, and other ugly stuff, so developing a healthier sugar-free version of them has been on my to-do list for ages. And this spring, I finally succeeded! What do you think? Aren’t they adorable?
I was happy with the frosting recipe, but it was too sweet for me. I had used 1/2 cup (120 ml) powdered erythritol, and that was clearly too much. In this final recipe, I’ve used only 1/3 cup (80 ml), and that gives it just the right amount of sweetness (according to my taste buds, at least!). Anyway, in my opinion, for optimal health the ultimate goal is to reduce the use of all sweeteners (even the natural ones) to a minimum, so that’s why even my dessert recipes aren’t that sweet (I think).
So, this frosting can do double duty as a perfect filling. But I really loved frosting this low-carb lemon cake with it (photo below)!
But by now you must be dying for the recipe. As always, first, here’s the video:
And here is the recipe. Enjoy!
- 2/3 cup = 160 ml heavy cream
- 1/3 cup = 80 ml powdered erythritol OR Confectioner's Style Swerve
- 3 egg yolks
- 6 oz = 170 g unsalted butter
- 1 teaspoon vanilla extract
- (optional: pinch unrefined sea salt)
- Place the cream, erythritol, and the egg yolks into a small saucepan.
- Heat over a low heat, constantly mixing, until the mixture thickens. Don't let it boil!
- Let the custard cool down to room temperature.
- When the custard is cool, beat the butter until fluffy and pale.
- Add the vanilla extract, the salt (if using), and the custard.
- Beat until fluffy, about one to two minutes.
- Use immediately as filling or frosting.
Hi! How can I make this into a chocolate frosting?
You can add a tablespoon or two dark cocoa powder. I’ve been planning to post a recipe for a chocolate buttercream frosting very soon, so stay tuned!
Can I pipe flowers using this kind of frosting?
Yes, it works well for piping flowers — I used it as well for piping roses.
I wanted a low-carb icing for the lamb cake I was making for Easter. I came across this recipe and decided to try it, even though I’m not the best at making custard. This icing was terrific. I put the custard over low heat and I think I almost cooked it too long (it was starting to get grainy), but it incorporated into the butter very smoothly and everyone at dinner liked it, even those not on a low-carb diet. It’s very creamy with a good consistency and just sweet enough.
Thank you for trying out the recipe! So happy to hear you all liked it.
This looks delicious! How much frosting does the recipe make? I am planning to make an 8″ round cake for my son’s birthday. Would one recipe be enough to cover it?
Hi Aly, yes, this should cover a 8-inch cake, however, if you want to pipe the frosting, I recommend to double the amount.
What could you replace the eggs with? We have an egg allergy in our household
I wonder if pinch of starch-free thickener like xanthan or guar gum would work thickening the custard instead of egg yolks. I haven’t tried it out, though.
How long is this good for? Does it have to be refrigerated?
Yes, it needs to be refrigerated. It would store up to three days.
Hi! Can I add food coloring to this frosting or would it ruin the whole thing? If yes, what kids do you recommend – regular or gel? Thanks much!
Hi, yes, you can add food coloring. Powdered colors don’t work that well but paste, liquid, or gel should work fine.
Hi, Is there a vegan version? Thanks Much!
Not yet, but there will be!
Very pretty! Frosting is everything. Thank you.
You’re welcome 🙂
I CANNOT wait to try this recipe! Looks soooooo good!
Thank you very much for your hard work on it.
Very Best, Ken
Thank you, Ken!! Hope you like it!