• Combine almond flour and confectioners’ sugar in a bowl and whisk together. Pass mixture through a fine-mesh sieve, pressing down on clumps.
• In a large bowl, beat the egg whites using a hand-mixer or stand-mixer on medium speed for 2 minutes until soft peaks form. Add the granulated sugar and beat on high for 2 more minutes until stiff, glossy peaks form.
• Add vanilla and beat on high for another 30 seconds.
• Gently fold in dry ingredients and repeat until mixture is smooth and shiny, (with no visible dry ingredients) and begins to run a little but not too runny. Think lava consistency. Do not overfold.
• Take a pastry bag fitted with a 1/2 inch round tip and fill with the batter.
• Line 2 baking sheets with parchment paper and pipe batter into 3/4-inch round circles, 1 inch apart.Tap the baking sheet firmly against the counter to release any air bubbles.
• Let stand at room temperature for 30 minutes until they form a skin.
• Preheat oven to 325 F.
• Bake for 10-12 minutes, rotating halfway, until cookies have risen and just set. The cookies should be able to just come off the baking sheet when you try to lift them. Let cool for 5 minutes then transfer to wire rack and let cool completely.