Combine the confectioner's sugar and almond flour in a bowl, then sift 3 times.
Place the egg whites in a large bowl and beat with an electric mixer until foamy. Add the cream of tartar, then beat until soft peaks form. Add the superfine sugar and beat on high speed until stiff peaks form. Add the vanilla extract and gently mix to combine. Sift the dry mixture into the egg mixture and gently fold to combine.