Line 3 baking sheets with parchment paper or silicone baking mats; set aside.

Sift almond flour and confectioner's sugar though a sifter to remove any large almond pieces; repeat if necessary. (You may also create your own almond flour by processing blanched almonds in a food processor until ground to a fine powder).

In a large, clean bowl, whip egg whites and cream of tartar with an electric mixer on medium speed until foamy. It is important that the bowl is free from any residue, including water, before whipping eggs. Any particles in the bowl may prevent egg whites from whipping.

When whites are foamy, increase speed on mixer to high and gradually add granulated sugar and almond extract; whip egg whites until stiff peaks form.

Fold flour mixture into egg whites with a rubber spatula until fully incorporated; the mixture should begin to flow like ribbons when lifted away from the bowl.

To test if mixture is ready, place a small dollop on a flat surface; when mixture flattens out completely it is ready.

Fill pastry bag or storage bag with batter and cut off the tip to create a 1/4 inch opening; pipe mixture onto baking sheets, creating 1 1/2 inch discs, spacing them 1 inch apart.

Tap baking sheet from the bottom to ensure that any air bubbles that may be trapped have escaped each cookie.

Set baking sheet aside for mixture to rest for approximately 1 hour; a shiny film will form on the top of each cookie.

Bake in a 325 degree F oven for 10-12 minutes, or until cookies are firm on top.

Remove from oven and cool completely.

When cooled, spread half of the cookies with your favorite filling - hazelnut spread, fruit preserves or homemade frosting.

Top each filled half with another cookie to create a sandwich.

Serve and enjoy!

Notes and Suggestions

You may substitute the almond extract in this recipe with your favorite flavorings such as peppermint, lemon or orange. To change the color of the cookie shells, add 1-3 drops of food coloring gel (which can be found at craft supply or baking supply stores) when adding the flavored extract.