In a medium bowl, combine flours, baking soda and salt. Whisk to combine. Set aside.
In the bowl of a stand mixer, combine butter and sugar. Mix on medium high until the mixture becomes light and fluffy. Next add one egg and almond extract to the bowl. Mix on medium speed until the egg is fully incorporated. Add the flour mixture to the butter mixture. Mix until just combined.
Place dough in plastic wrap and form into a ball. Wrap well and refrigerate for at least 2 hours or up to overnight.
Preheat oven to 325°F and line baking sheets with parchment paper. Place one egg in a small bowl and beat well.
Grab about 1 tablespoon of dough and form into a 1-inch ball, we used a small cookie scoop. Place the dough ball on the cookie sheet one inch apart to allow for spreading and press to slightly flatten. Using a pastry brush, brush the beaten egg over the cookie and gently press an almond slice on top.
Bake for 12-15 minutes, or until the cookies start to turn a golden brown.
Remove the pan from the oven. To make perfectly round cookies, place a glass or biscuit cutter over the cookie and circle around the cookie gently to form a perfect circle. Allow the cookies to cool for 5 minutes on the sheet pan. Transfer to a cooling rack to finish cooling.
