Prepare aquafaba by reducing the liquid from two cans of chickpeas over medium heat until halved and cool.

Preheat your oven to 150°C (or 130°C for fan-assisted ovens).

Whip the cooled aquafaba with cream of tartar until frothy, then add caster sugar gradually until stiff peaks form.

Sift together ground almonds and icing sugar, then gently fold into the whipped aquafaba mixture without overmixing.

Pipe 2-inch circles on a lined baking sheet, letting them sit for 20-30 minutes until the surface is matte.

Bake the macarons for approximately 18 minutes, then cool completely on the baking sheet.

Beat together icing sugar and vegan margarine, add vanilla extract, and mix until fluffy, adjusting with plant-based milk if needed.

Assemble macarons by pairing shells, piping buttercream filling onto one, and sandwiching with another shell.