This swiss meringue buttercream is silky smooth and perfectly pipe-able. It is hands down the best sugar free frosting I've ever made and is worth the effort. Up your keto baking game with this amazing vanilla buttercream recipe.
Make sure the bowl of a stand mixer is very clean and set over a pan of barely simmering water. Add egg whites and both sweeteners.
Whisk gently but constantly, until the sweeteners have dissolved and egg whites are hot and slightly frothy. They should reach about 150F on an instant read thermometer.
Transfer the bowl to the mixer and attach the whisk. Whip the egg whites at medium high speed until they are thick and glossy and the bottom of the bowl is no longer warm, anywhere between 5 and 10 minutes. The temperature should be about 90F on an instant read thermometer.
Start adding the butter cubes one at a time until full incorporated and the frosting is smooth and creamy. Turn stand mixer to medium low and add the vanilla and salt until combined.
Spread or pipe on your favorite keto cakes and cupcakes! This frosting also freezes really well. Let it come to room temperature again and rewhip lightly before frosting.
NOTE: I know I will be answering this question over and over so let me just say it straight up. You need the two different sweeteners here! A combination of an erythritol based sweetener, such as Swerve, and one that keeps things softer, such as Bocha Sweet, xylitol, or possibly allulose, is necessary to achieve the correct consistency.
How to rescue sugar-free Swiss Meringue Buttercream:Curdled frosting: If the frosting has little lumps of butter, it means it's a bit too cold to fully incorporate together. Simply sit the bowl over the pan of water and rewarm very gently. Once it's looking a bit melted around the edges, put it back on your stand mixer and turn it on low. Slowly increase the speed and whip it until it comes together. Soupy frosting: If the buttercream is thin and liquidy, it means it's too warm. Refrigerate for 10 to 20 minutes, until it's hardened around the edges but still soupy in the middle. Then whip until it thickens and firms up.
Serving: 1serving = about 1/4 cup | Calories: 109kcal | Carbohydrates: 0.1g | Protein: 1g | Fat: 10.7g