Sift almond flour, powdered sugar, and cocoa powder together into a large bowl.

Beat egg whites with a pinch of salt until soft peaks form, gradually adding granulated sugar and vanilla until stiff peaks appear.

Fold dry ingredients into egg whites using the macaronage technique until the batter flows slowly off the spatula.

Pipe batter onto a parchment-lined baking sheet, then tap to release air bubbles.

Let shells rest 30–60 minutes until a thin skin forms.

Preheat oven to 300°F (150°C) and bake shells 15–18 minutes, rotating halfway through. Cool completely.

Beat butter for buttercream until creamy, gradually adding powdered sugar and cocoa powder, alternating with heavy cream and mixing in vanilla.

Pair shells of similar size, pipe buttercream on one, and sandwich with another.

Refrigerate assembled macarons for 24 hours, then bring to room temperature before serving