Mix together all purpose flour, salt, and baking soda. Whisk to break up clumps. Set aside.
Add cubes of cold butter to sugar and ground almond flour. Mix in a food processor until well combined and there are no more chunks of butter.
Then add in eggs and almond extract to the butter/almond flour mixture and pulse until well combined.
Add flour mixture into the butter/almond flour mixture. Mix in the food processor. Wipe down the sides of the bowl with a spatula and mix again. Mix until the ingredients are well combined. It should look crumbly.
Form dough into a tight flat disc and cover with plastic wrap. Refrigerate for at least 1 hour.
Take dough out to thaw. Preheat oven to 350 degrees F. When dough has slightly warmed and is pliable, break into small pieces and roll into even sized balls. Flatten the balls into 1/4 inch thick disks onto a parchment-lined cookie sheet, spacing them at least 1/2 inch apart.
Top cookies with several slivers of sliced almonds, gently pushing the almonds into the cookies to help them stick. Then brush generously with egg wash (1 beaten egg).
Place cookies in the middle rack of the oven. Depending on the size and thickness of your cookies, bake for 12-17 minutes or until the cookies are golden brown on top. Rotate halfway through to ensure even baking. Tap the middle of a cookie to see if it is dry/cooked through. If it is still soft in the middle, lower your oven to 250 degrees F and continue to bake them for another 5-10 minutes to dry out the middle.
Then turn off your oven, leave the door slightly open, and allow cookies to sit in oven for another 10-15 minutes to allow them to dry out and become crispy in the middle.
Your cookies are done when they are crispy/dry in the middle and the tops are golden brown. Cool for another 30 minutes outside of the oven and they will be ready to eat.
