Leave butter at room temperature for at least 1 hour until softened, then whip it with a whisk until smooth.

Add powdered sugar and continue whisking until well combined.

Add vanilla extract and mix. This step is optional.

Sift cake flour, cocoa powder, and salt into the mixture.

Gently fold the mixture with a spatula, lifting from bottom to top. Avoid overmixing.

Once the dough starts to clump, use your hands to form it into a cohesive ball.

Scoop the dough into cookie shapes using a scoop. Preheat the air fryer to 150°C for 5 minutes.

Place the scooped cookies on a greased tray and let them rest while the air fryer preheats.

Transfer cookies to the air fryer lined with parchment paper. Bake at 150°C for 15 minutes.