Almond macarons with almond buttercream

almonds (or almond flour); almonds can be blanched and slivered, unblanched and sliced; don't use whole because it still has too much moisture in it.

powdered/confectioner's sugar (Don't make your own because it won't work unless your processor is POWERFUL. The kind with cornstarch in it is okay.)

granulated sugar

egg white (close to 3 eggs, but you will have some leftover--weigh it!)

butter, at room temperature

powdered sugar (a fat ½ cup)

almond extract