Chocolate Gems

Directions

1. Cream the butter using a hand mixer, and then add the sugar and vanilla, and mix until smooth.
2. Sieve the flour with the cocoa powder, and a pinch of cinnamon and salt, and add to the mixture.
3. Mix vigorously and divide into 2 doughballs.
4. Allow the dough to rest in the refrigerator for 30 minutes.
5. Shape each dough ball into a 4-centimeter diameter cylinders. Avoid holes forming in the dough by flattening by hand and then rolling into a cylinder.
6. Wrap each cylinder in plastic film and leave in the refrigerator for 2 hours.
7. Preheat the oven to 180 degrees Celsius.
8. Beat the egg yolk.
9. Cut the cylinders into 1.5-centimeter thick disks and brush with the egg yolk.
10. Place on sheet of parchment paper sprinkled with sugar. Turn disks two or three times to allow the sugar crystals to completely cover the disks both sides.
11. Place on a baking sheet spaced apart.
12. Bake for 15 to 18 minutes, turning halfway through cooking.
13. Allow to cool before serving.