Step 1

Add the freeze-dried raspberries to a food processor and blitz for a few minutes until they turn into a powder consistency. Allow the powder to settle in the food processor for a minute before opening the lid. Then pass the powder through a fine-mesh sieve to remove any seeds. If you're using raspberry powder you can skip this step.

Step 2

Add the aquafaba and sugar to a large bowl and place the bowl on top of a saucepan with a few inches of water in the bottom (known as a bain-marie or water bath). Bring the temperature up to medium and allow the mixture to heat for a few minutes until the sugar is dissolved. Check the sugar has dissoled by stirring the mixture with a spoon, the syrup will coat the spoon and shouldn't have visable granules.

Step 3

Remove the bowl from the heat, and use an electric whisk or stand mixer with a whisk attachment to beat the mixture on high speed for 15-20 minutes until the mixture is completely cooled and glossy. The mixture should become stiffened and glossy.

Step 4

Reduce the speed to low-medium and slowly add the chunks of butter to the meringue, one at a time, allowing the mixture to incorporate for about 5 seconds between each one. The mixture will flatten as you add the butter, just continue to add the butter as it will stiffen when the full amount of butter is incorporated.

Step 5

Once all the butter has been added the mixture be thick like buttercream, bring the speed back up to medium-high and continue to whisk on low for 5-10 minutes until the mixture is fluffy and lightened in color. If the mixture looks split, don't worry it will come together with enough blending.

Step 6

Lastly, add the vanilla extract and raspberry powder to the buttercream and fold the ingredients with a spatula (this prevents the powder from puffing up when you whisk the ingredients). Continue to whisk for a couple of minutes until combined.

Step 7

For best results, use the buttercream immediately to frost your vegan cake or cupcakes. You can store this buttercream in an airtight container in the fridge. It will harden when chilled, so before use, allow it to come to room temperature until it comes back to a creamy consistency.