The Ultimate Guide to Making Keto Frosting

The Ultimate Guide to Making Keto Frosting

Sweeteners, Methods, and Variations

So you’ve made keto cake, cupcakes, or brownies, now what? Surely you’d like some frosting on top! Regular frosting is full of sugar, meaning it won’t fit into a keto diet, and if you’ve done any keto baking at all you’re probably well aware that non-caloric sweeteners don’t function quite like standard sugar does.

While some types of frosting aren’t a match for sugar free baking, a standard buttercream luckily is. When looking to make a sugar free version of a frosting, you’ll want to types of frosting that utilize sugar for structure, such as Italian meringue or royal icing. That’s why buttercream makes the most sense as a go-to—unlike many others, its structure is created mainly from fat.

Let's break down what goes into a keto buttercream frosting and what ingredient ratios work best.

The Sweetener

If it's not full of sweetener, then it's not frosting! The main difference between powdered sugar and a powdered keto sweetener, outside of the obvious fact that a keto sweetener is sugar free, is that powdered sugar contains cornstarch. This functions as a stabilizer, helping to keep the texture of frosting the same even days later.

If you can spare 1 or 2 grams of carbs per serving, you can sift your own powdered keto sweetener with cornstarch and arrowroot starch. Cornstarch averages 7-9 grams of carbohydrates per tablespoon, and even a 1/2 tablespoon added to several cups of powdered keto sweetener would help keep your frosting’s texture sound for longer. Here are the best choices for a powdered keto sweetener.

Powdered Erythritol

Powdered erythritol is sold by assorted brands, with the most popular being Swerve. Because Swerve has prebiotics added that make it more stable for baking, it's the easiest and wisest choice for a keto frosting sweetener, as it will hold up best for the duration of your baked good's shelf life. It's important to note that though erythritol is 70% as sweet as sugar, Swerve measures cup for cup with it. That means that if you use a different powdered erythritol, you'll want to use a ratio of 30% more.

To use Swerve in a buttercream frosting, a standard ratio of 2:1 sweetener:butter, plus as much milk as is needed for thinning, can be employed. For other powdered erythritol, you'll want a ratio of 2.4:1 of sweetener: butter.

Powdered Monk Fruit

Straight monk fruit extract is similar to stevia, in that it is many times as sweet as sugar. Because of this, it is mixed with other non-caloric sweeteners (usually erythritol) when sold powdered. The most common label for this is as Lakanto, which measures cup for cup with sugar.

To use powdered monk fruit in a keto frosting, the standard ratio of 2:1 sweetener:butter, plus as much milk or heavy cream as is needed for thinning, can be employed.


If you have a blender and granulated keto sweetener, you can make your own powdered keto sweetener in a matter of moments. Simply blend the sweetener on high until it's powdered. If you aren't opposed to adding a small amount of cornstarch or arrowroot to your powdered sweetener, that can go in the blender along with the granulated sweetener. The ratio of sweetener to butter will depend on what sweetener you choose.

Because xylitol has a cooling effect in the mouth and is dangerous to pets, it's a less ideal choice than powdering your own erythritol or monk fruit.

The Fat(s)

It's butter that's in the name, but any frosting can be made more stable at room temperature with the addition of shortening. It's not unheard of, in both keto and vegan baking, to use coconut oil in frosting. Let's look at what fat works best.


There's no doubt that a quality grass fed butter has health promoting benefits. Even more so, it has more flavor than other frosting-appropriate fats. Because of that, your frosting will taste best if you use butter for the bulk of the fat, if not all. The only reason to consider other fats are for stabilization, as butter can become very soft at room temperature.


If you want your frosting to hold up well without refrigeration, shortening is your safest choice. You can replace up to 50% of the butter in your recipe with shortening. You’ll treat it similarly to the butter, beating the fats together. Because shortening has no taste, but does have an inherent greasiness, using more than half in your frosting could lead to a less desirable result.

If you'd like to use shortening in your keto frosting for stabilization, a ratio of 1:1 to butter should be the highest, and 1:2 to butter will be best to keep the buttery flavor while still increasing the melting temperature.

Coconut Oil

Using coconut oil in frosting has grown in popularity due to its healthy components, such as MCTs. However, at room temperature coconut oil is very soft. Because of that, it's only a suitable fat for keto frosting if you plan on keeping your baked goods in the refrigerator. Coconut oil will whip up only if it's at just the right temperature: warm enough to be soft, but not warm enough to melt—the difference of which is only a few degrees. Since beating with an electric mixer generates some heat, that can get tricky quickly. If you do try coconut oil in frosting, know that there may be a hit or miss factor.

The Flavor

Similar to standard frosting, keto frosting can be any flavor you imagine. You should avoid sweetened cocoa or a fruit puree, but there are still plenty of ways to flavor your frosting regardless. Use the following flavor addition quantities for a single cake layer frosting recipe:

  • 2 cups powdered keto sweetener
  • 1 cup softened butter
  • 1-2 tablespoons unsweetened non-dairy milk or heavy cream thinned 1:1 with water


  • 1 1/2 teaspoons vanilla extract, added before milk/cream is added to thin


  • 1/4 cup cocoa powder, added with powdered sweetener at the start; you may need 1-2 additional tablespoons of liquid


  • Add 1 teaspoon raspberry, lemon, orange, or other fruit extract before milk/cream is added to thin

Cream Cheese

  • Reduce butter to 1/4 cup, and replace with 3/4 cup softened cream cheese


  • Use coconut milk for the liquid; add 1 teaspoon coconut extract before coconut milk is added to thin, then fold in 1/4 cup toasted coconut shreds (unsweetened) after finishing the frosting

The Color

Natural food coloring has come a long way in recent years! If you like a colorful frosting, simply add natural food coloring prior to adding liquid to thin, drop by drop until the desired color is reached.


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