Make meringue and whip until stiff peaks form.
Add the sifted almond meal and powdered sugar and fold to combine.
Mix until you can draw an unbroken figure 8 with the batter.
Pipe out the macarons and then bang on the counter to remove any bubbles.
Add sprinkles if using, then leave to dry until a skin forms.
Bake until the shells can be cleanly lifted off.
Pair up the shells and sandwich with buttercream.