The Best Keto Chocolate Buttercream Frosting

I’ve made a lot of keto frostings over the years, and this chocolate buttercream is the one I keep coming back to. The secret is using both cocoa powder and melted sugar-free chocolate chips instead of picking one or the other. Cocoa gives you that deep, dark chocolate backbone, and the melted chips round it out with richness and body. I tested it both ways early on, and the single-source version always tasted flat by comparison.

The base is simple: softened butter whipped until it’s light and fluffy, then Swerve confectioners, cocoa powder, melted chocolate chips, heavy cream, salt, and vanilla. I use heavy whipping cream instead of almond or coconut milk because it gives the frosting a silky texture that pipes cleanly. Plant milks thin it out unpredictably, and I got tired of trying to rescue batches that wouldn’t hold shape.

This makes enough to generously frost a two-layer 9-inch cake or about 24 cupcakes. I usually have a little left over, which goes straight into the fridge for the next batch of keto cupcakes or as a topping for a birthday mug cake. It’s also the frosting I use for my keto chocolate trifle when I want something layered and impressive without spending all afternoon in the kitchen.

One thing I want to mention: the sweetener matters here. I specifically call for Swerve confectioners (the powdered version) because granular erythritol stays gritty in frosting no matter how long you beat it. I learned that the hard way years ago and wasted an entire batch. If you’re using a different low carb sweetener, make sure it’s a powdered or confectioners-style variety.

A reader named Chris actually forgot to add the sweetener entirely and still thought it tasted good. He added some later and agreed it’s better with it, but the chocolate quality carries this recipe on its own. That’s the benefit of the double-chocolate approach. You’re not relying on sweetener to do all the heavy lifting.

If you love chocolate desserts, this frosting pairs with just about everything. I’ve used it on keto chocolate mousse as a piped topping, spread it between cookie layers, and even eaten it straight from the bowl with zero regrets. It keeps in the fridge for up to a week, and you can freeze it for up to three months.

The most important step is beating the butter long enough. I go a full 2-3 minutes with my electric mixer until it’s pale and fluffy. If you rush this, the frosting ends up dense instead of light. Room temperature butter is non-negotiable here.

Once the butter is whipped, add everything else and keep beating until it’s smooth. If the consistency is too thick to spread, add another tablespoon of heavy cream. If it’s too thin (this happens if your butter was too warm), pop the bowl in the fridge for 10 minutes and re-whip. I’ve done both fixes more times than I can count.

For piping, this frosting holds up well with a standard open star tip. I use it on my keto mug brownie when I want something a little fancier than a spoonful on top. The low carb sweetener dissolves completely as long as you’re using a confectioners-style variety, so you get a clean, smooth pipe every time.