Sift the almond flour/powdered sugar mixture over the whipped egg whites. Gently fold the mixture running the spatula clockwise from the bottom, up around the sides and cut the batter in half, as shown in this video
. The batter will look very thick at first, but it will get thinner as you fold. Be careful not to over mix it though. Every so often test the batter to see if it reached the right consistency. To test the batter, drop a small amount of the batter and count to ten. If the edges of the ribbon are dissolved within ten seconds, then the batter is ready. I repeat, do NOT mix again. If you still see edges, fold the batter couple more times and test again. This step is so crucial, so please make sure to test often to ensure not to over, or under mix the batter.