Preheat oven to 350 degrees. Line two cookie sheets with parchment paper.
Pulse the almonds in a food processor until fine. Do not overprocess. Transfer almonds to the bowl of a stand mixer fitted with the paddle attachment. Add butter, sugar and vanilla and beat together on medium speed. (Alternatively, do this part with an electric hand mixer).
Stir in the flour until combined. Form the dough into balls the size of golf balls. Place cookie dough balls onto the prepared baking sheet. Bake cookies for 12 minutes, then remove from oven.
Using the back of a fork, smash the cookies down, making a crisscross pattern. Return to the oven and bake another 2-4 minutes, until slightly golden on the bottom.
Transfer cookies from the cookie sheet to a wire rack. Place confectioners' sugar into a shallow bowl. Once cooled, dip the cookies in powdered sugar to coat both sides. Tap off the excess sugar and dip them again to coat both sides.