1. In a mixing bowl, combine almond flour and confectioners’ sugar. Using a fine-mesh sieve, strain the mixture, pressing down on any clumps.
2. In a large mixing bowl, beat the egg whites on medium speed for 2 minutes, or until soft peaks form. Add the granulated sugar and continue to beat on high for 2 minutes, or until stiff, glossy peaks form.
3. Add the vanilla extract and continue to beat on high for 30 seconds.
4. Gently fold in the dry ingredients and repeat until the mixture is smooth and shiny (no visible dry ingredients) and starts to run a little but not too much. Consider the consistency of lava. Make sure not to overfold.
5. Fill a pastry bag fitted with a 12 inch round tip with the batter.
6. Line two baking sheets with parchment paper and pipe the batter into 34-inch round circles, spacing them 1 inch apart.
7. To release any air bubbles, firmly tap the baking sheet against the counter.
8. Allow to stand at room temperature for 30 minutes, or until a skin forms.
9. Preheat the oven to 325 degrees Fahrenheit.
10. Bake for 10-12 minutes, rotating halfway through, or until cookies have risen and are just set. When you try to lift the cookies, they should just fall off the baking sheet.
11. Allow to cool for 5 minutes before transferring to a wire rack to cool completely.

Filling (Vanilla Buttercream):

1. Cream butter with a hand mixer or a stand mixer until soft and smooth.
2. Mix in the powdered sugar, milk, and vanilla extract until the mixture is light and fluffy.

How to Make Macarons:

1. Fill a piping bag fitted with a round tip with the buttercream filling.
2. Fill half of the cookies with a swirl of filling.
3. Sandwich the remaining cookie halves together.