Place the powdered sugar and almond flour in a food processor or blender. Pulse for 30 seconds until combined and fine in texture. Set aside.
In a stand mixer, beat the egg whites, salt and Watkins All Natural Original Gourmet Baking Vanilla® together on medium speed. Switch to high speed and beat just until stiff peaks form. Fold in the sugar 1 tablespoon/15 mL at a time until combined. Fold the almond flour mixture into the egg whites until combined. The mixture will be smooth, sticky and glossy when it is done. Let the batter rest for 10-30 minutes.
Line 2-3 baking sheets with ungreased parchment paper and prepare your piping bag. Fill the piping bag and pipe small (about 2-inch/5-cm) circles on the baking sheets. Gently tap the sheets to release bubbles and sprinkle cinnamon on the top of each cookie. Let the cookies rest for 45-60 minutes.
Preheat oven to 325°F/160°C. Bake sheets one at a time for 10 minutes each, then remove and allow cookies to cool completely before removing from the sheets and assemble with filling.
In the bowl of a stand mixer, beat the butter and brown sugar for one minute on high speed, until the butter is smooth and creamy. Beat in the powdered sugar until it is completely blended and then add in Watkins All Natural Original Gourmet Baking Vanilla® and Watkins Organic Ground Cinnamon. Mix until blended.
Total Time: 2 Hours
Prep Time: 90 minutes
Cook Time: 10 minutes (for each sheet pan)