(1.2 oz,3Tbsp) unsalted butter, room temperature • (1.2 oz, 4 Tbsp) powdered sugar • egg white, room temperature • (0.35 oz, 1.5 Tbsp) almond flour • (0.9 oz, 2 and 4/5 Tbsp) cake flour, or all-purpose flour • cocoa powder, sugar-free • vanilla oil, optional • chocolate, for dipping