Prepare a baking sheet with parchment paper.

In a bowl, mix almond flour and powdered sugar together.

In a separate bowl, whip the egg whites until foamy, then gradually add granulated sugar, continuing to whip until stiff peaks form.

Gently fold the almond flour mixture into the whipped egg whites, being careful not to deflate the mixture.

Add the vanilla extract and salt to the mixture and blend gently.

Pipe the mixture onto the prepared baking sheet in small circles.

Let the piped cookies rest for 30 minutes to form a skin on the surface.

Preheat the oven to 300°F (150°C).

Bake for 15 minutes or until they lift cleanly from the parchment paper.

Allow to cool completely before filling with buttercream.

In a mixing bowl, beat the softened butter until creamy.

Gradually add powdered sugar and vanilla extract while mixing.

Stir in heavy cream until the desired consistency is reached.