Preheat your oven to 300°F (150°C) and prepare two baking sheets lined with parchment paper.

In a double boiler, combine the egg whites and granulated sugar, whisking until frothy. Transfer to a stand mixer and whip until stiff peaks form.

Sift almond flour, cocoa powder, and powdered sugar together. Fold into the meringue until a 'lava-like' consistency is achieved.

Transfer batter into a pastry bag and pipe 1.5-inch circles onto the baking sheets. Tap to release air bubbles.

Bake for 13 minutes, rotating sheets halfway through. Ensure the tops are matte and dry before removing.

Cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.

In a mixing bowl, beat peanut butter and softened butter, then gradually add powdered sugar, vanilla, and salt until fluffy.

Pipe the filling onto the flat side of one macaron shell and sandwich with another shell. Optionally, drizzle with melted chocolate.