I am not vegan myself, but I have been consistently impressed with new and innovative techniques that are available to produce great desserts without the use of animal products. In some cases, vegan desserts and pastries taste even better than those that are traditionally made. However, in some cases, it can be very challenging to produce a baked good that doesn't "taste vegan" or have a different texture that gives it away. After all, a majority of baking recipes were developed specifically to utilize eggs, milk, or butter in the first place and omitting them can be a kitchen disaster. But I am here to say that if you are vegan or have allergies, you don't have to be deprived of a dreamy buttercream made with Italian meringue.
Aquafaba, or the liquid from a can of garbanzo beans, has a protein content that behaves remarkably like egg whites. When it is whisked for an extensive period of time at high speed, it will foam and whip to soft and stiff peaks just as normal egg whites do. The bonus is that aquafaba is actually more stable than egg whites and can't be over whipped. This allows it to withstand the 20+ minute emulsion process that this decadent frosting has to go through before it achieves its smooth and buttery state. The payoff is worth the work, as this buttercream is not only addicting but incredibly pipe-able and easy to work with. As you can see on the cake above, it is incredibly smooth and ices cakes and cupcakes like a dream.
This recipe is challening and technical. I recommend reading through more than one recipe or searching some videos on Youtube before diving in as it requires some careful temperature monitoring.
Notes: I recommend doubling the recipe if you plan on icing a large cake or more than 2 dozen cupcakes.
Yield 6 cups
1 1/2 cups of Low Sodium Garbanzo Bean liquid from the can reduced to 1 cup In this step you will need to reduce the liquid in a saucepan until you have about 1 cup remaining. Allow it to cool to room temperature.
1/4 teaspoon of cream of tartar
1 cup of white granulated sugar
1/4 cup of water
1 1/2 lbs. (680 grams) of vegan butter. Must be made for baking. (optional to use regular butter) room temperature and sliced into pieces
3/4 cup (96 grams) of vegetable shortening
3 teaspoons of vanilla extract
1 teaspoon of salt
In a medium saucepan, combine sugar and water and affix a candy thermometer to the side. Turn the heat to medium high and allow it to boil to 240 degrees Fahrenheit or softball stage. You will have a sugar syrup as shown in the video. This will take some time depending on the level of heat, however it should take around 9-10 minutes
In the bowl of a stand mixer, add the aquafaba and cream of tartar and whip on high continuously while the sugar mixture is coming to temperature. Whip to stiff peaks.
Once the sugar syrup has come to temperature and the meringue reaches stiff peaks, stream the hot syrup into the meringue slowly as it continues to whip (see video)
(Note: in the video, I had doubled the recipe and that's why there's so much volume. In a single recipe, there won't be as much volume)
Once all of the syrup is poured in, the meringue will be very warm, well over 100 degrees F. You must allow it to cool to at least below 100 degrees before you proceed to add the butter. I used a temperature probe and tested at the bottom to the top. Let the mixer continue to run on high through the cooling process. To speed this up, I put a bag of ice under the mixer bowl to cool it and it cut the time down significantly.
Once the meringue has cooled, slowly add pieces of room temperature butter and shortening, waiting a few seconds in between. At this point you can add your vanilla, salt, and food coloring if desired.
Important: Once all the fat is added, the meringue will deflate down into a soup. DO NOT BE ALARMED! It knows what it's doing. This is the emulsion process where the fat molecules are reluctantly binding with water molecules. Continue to let it whip on high through this and you will see it transition into a whipped buttercream state. What a relief!
At this point, the process is complete and you should have a beautiful and smooth buttercream. I recommend using it immediately rather than storing.
To smooth out cold buttercream: The buttercream will be very solid once it's cold. When you are ready to use it, simply put in the stand mixer affixed with the paddle attachment and let it mix on low until smooth. Sometimes liquid separation occurs when the buttercream comes to room temperature. If so, add powdered sugar and continue to whip until smooth.
Good Luck! Please tag me or leave feedback when you try this. As always, I love to know how my recipes turn out for others. If there's anything I can add for clarity please e-mail me or leave a comment below.