Sift the powdered sugar, salt, and almond flour together.
Using a stand mixer, whip the egg whites on low speed until frothy. Gradually add the sugar, and then whip on high speed until stiff peaks form, add the almond extract. The egg whites should be glossy and thick.
Fold half of the almond mixture into the egg whites and then add the rest. Fold the mixture 15 to 20 times; the batter will be thick and fall slowly when dripped from the spatula. You can separate the batter and mix in food coloring of your choice.
Pipe 1-inch circles onto baking sheets lined with silicon mats or parchment paper. Let rest until a skin forms on top and is dry to the touch, 15 to 30 minutes.
Bake for 10 to 12 minutes, rotating the pans halfway through the baking time. If you are baking two sheets at a time, the bottom and top sheets should be rotated to prevent over browning on the bottom. If only baking one sheet at a time, bake on the bottom rack first for 5 minutes with an empty sheet on top. After 5 minutes, rotate the sheet and move the bottom sheet to the top and the top sheet to the bottom.
Make sure they are set, if you touch them they will be firm.
Let them cool for about 10 minutes on the baking sheet and then take them off. Fill as desired with your favorite chocolate ganache, jams, or flavored buttercream icing.