Pulse confectioner’s sugar and almond flour in food processor. Sift mixture 2 times.
Preheat over to 325 degrees F. Whisk egg whites with a mixer on medium speed until foamy. Add cream of tartar, and continue to whisk until soft peaks form. Reduce speed to low and slowly add superfine sugar. (pulse granulated sugar to get superfine sugar). Once all sugar is in, increase speed to high and continue until stiff peaks form, about 8 minutes.
Sift flour mixture over the egg whites and fold until mixture is smooth and shiny. Do not overmix.
Transfer batter to a pastry bag with a 1/2 in plain round tip and pipe 3/4 inch rounds 1 inch apart on parchment-lined baking sheets, dragging pastry tip to the side of rounds rather than forming peaks. Tap bottom of baking sheet against table to release any trapped air. Let stand at room temperature for 20-30 minutes or until a skin has formed. You should be able to touch the batter without it sticking to you.
Bake one sheet at a time, rotating halfway through, until macarons are crisp on the outside, about 15-20 minutes. let macarons cool on sheet for 3 minutes, then transfer to wire rack.
Sandwich same size macarons with filling. Wrap and let mature in fridge for 24-48 hours before eating. You can also freeze macarons for up to two months. Bring to room temperature before serving.