1. Cut the butter into small pieces and let it soften at room temperature.
2. Sift in the granulated sugar and stir evenly.
3. Add eggs and mix well.
4. Sift in flour, almond flour, and salt, and add vanilla extract.
5. Knead into a uniform dough.
6. Add cocoa powder to the dough, knead it into a brown dough, wrap it in plastic wrap, and keep it in the refrigerator for about half an hour.
7. Place the dough between two pieces of baking paper, squeeze it, and use a rolling pin to roll it into a uniform thickness of about 0.4mm.
8. Use a mold to cut out the shape of the biscuit.
9. Use thick tin foil and fold it three times into a strip.
10. Fold the tinfoil paper strip to a corner of about 0.6cm.
11. Use a homemade mold to cut out the bayonet of the rim of the cup.
12. Preheat the oven to 170 degrees, put it in the oven and bake for about 12 to 15 minutes.
13. Take a large bowl, add powdered sugar and egg whites.
14. Stir at low speed with an electric whisk for about 10 minutes.
15. Put the white icing sugar in the piping bag.
16. Just draw a pattern on the biscuit.
