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 a large bowl. Add butter, sugar and vanilla and beat together.
Stir in the flour until combined. Form the dough into balls the size of golf balls. Place 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.
Cool the cookies on a wire rack. Once cooled, dip them in powdered sugar to coat both sides.