Aqua faba peppermint macarons with candy cane pieces.
Please read the notes before attempting this recipe. It's a difficult one to get right first time so I recommend following the instructions to a tee.
Place the aqua faba and cream of tartar into a bowl. Whisk it using an electric whisk or stand mixer until it becomes pale and frothy.
Slowly add in the caster sugar, a little bit at a time. Keep whisking until it becomes white and glossy like meringue and holds stiff peaks. When it's ready, you will be able to tip the bowl upside down without the mixture moving. Please note that this does take a bit longer than it would with egg whites so be patient and keep whisking! It will come together eventually.
Sift the ground almonds and icing sugar into the bowl. Use the back of a spoon to push any stubborn pieces through the sieve.
Use a rubber spatula to gently fold the sugar and almonds into the meringue mixture until soft and smooth. Be careful not to overmix. When you can draw a figure of 8 using your spatula without the mixture breaking, it's ready. You can also test by spooning a small amount onto some baking paper. If it still has a point or bumps on top after 10 seconds, it needs to be mixed more. It should spread out very slowly and be smooth on top.
Transfer the mixture into a piping bag and pipe 2-inch macarons onto your baking sheet.
Slam the tray on the counter a few times to get rid of any air bubbles and let them sit at room temperature until you can touch them without the mixture sticking to your fingers. This usually takes around 20-30 minutes but may take longer.
In the meantime, preheat your oven to 150°C/300°F. (130°C/275°F if you're using a fan or convection oven)
Once rested, bake the macarons for 18 minutes. You can test if they're ready by trying to wobble the top of one with your fingers. When they're done, they will be firm on top without much movement.
Let the macarons sit on the tray until they are completely cool.
Whisk the butter in a bowl until light and fluffy. Add in the icing sugar bit by bit until smooth, adding the plant-based milk to loosen it.
Add the peppermint extract and whisk again until the buttercream is light and airy.
Pipe a swirl of buttercream onto half of the macarons and use a twisting motion to sandwich them together with another macaron half.
Use your fingers to place the candy cane pieces around the edges, making sure they stick to the buttercream.