Steps

1. Bring the unsalted butter for both the vanilla and cocoa portions to room temperature. **Key Tip:** If using a microwave to soften, heat in short bursts, checking every few seconds to avoid melting completely.
   🕒 01:12
2. Preheat your oven to 170°C (340°F).
   🕒 07:16
3. In a bowl, combine the room-temperature unsalted butter (80g) for the vanilla dough with granulated sugar (40g). Mix until the mixture is soft and glossy. **Key Tip:** Using granulated sugar instead of powdered sugar creates a delightful crunchy texture.
   🕒 01:32
4. Add the egg yolk (1 pc) for the vanilla dough and mix until uniform. **Key Tip:** Egg yolks contribute to the unique crumbly texture and rich color of Diamant cookies.
   🕒 02:00
5. Stir in the vanilla extract (3-4 drops).
   🕒 02:17
6. Sift in the cake flour (55g) and bread flour (55g) and mix by folding with a rubber spatula, as if cutting through the dough. **Key Tip:** Be careful not to overwork the dough after adding the dry ingredients.
   🕒 02:29
7. Once no dry flour is visible and the dough starts to come together, gently press the dough with the spatula to incorporate any remaining flour until smooth.
   🕒 03:25
8. When the flour is fully incorporated, gently press the dough together with your hands to form a cohesive ball.
   🕒 03:41
9. Wrap the vanilla dough in plastic wrap and refrigerate.
   🕒 03:50
10. In a bowl, combine the room-temperature unsalted butter (80g) for the cocoa dough with granulated sugar (40g) and salt (1g). Mix until the mixture is soft and glossy. **Key Tip:** Cocoa and a pinch of salt pair exceptionally well together.
    🕒 01:32
11. Add the egg yolk (1 pc) for the cocoa dough and mix until uniform. **Key Tip:** Egg yolks contribute to the unique crumbly texture and rich color of Diamant cookies.
    🕒 02:00
12. Sift together the cake flour (45g), bread flour (45g), and cocoa powder (20g) before sifting them into the bowl. Mix by folding with a rubber spatula, as if cutting through the dough. **Key Tip:** Mix the cocoa powder well with the flours before sifting to ensure even distribution. Be careful not to overwork the dough after adding the dry ingredients.
    🕒 02:29
13. Once no dry flour is visible and the dough starts to come together, gently press the dough with the spatula to incorporate any remaining flour until smooth.
    🕒 03:25
14. When the flour is fully incorporated, gently press the dough together with your hands to form a cohesive ball.
    🕒 03:41
15. Wrap the cocoa dough in plastic wrap and refrigerate.
    🕒 03:50
16. Take out the chilled vanilla and cocoa doughs from the refrigerator and knead them slightly to achieve a uniform softness throughout. **Key Tip:** Trying to roll out hard dough will cause it to crack. Knead the entire dough until it reaches a consistent, pliable consistency, not just a small section.
    🕒 04:07
17. Once the dough is uniformly softened, gently compress it with your hands to remove any air pockets.
    🕒 04:40
18. Roll the dough into logs, approximately 3cm (1.2 inches) in diameter. **Key Tip:** Rolling the dough with a "figure-eight" motion will prevent finger marks and create a smoother surface.
    🕒 04:55
19. Wrap each dough log tightly in plastic wrap, twisting the ends like a candy wrapper to create a firm shape. **Key Tip:** Tightly wrapping the dough in plastic wrap will prevent wrinkles and result in a smooth cookie surface.
    🕒 05:25
20. Once shaped, freeze the dough logs.
    🕒 05:44
21. Lay out two large sheets of plastic wrap and spread the granulated sugar for coating evenly on one sheet.
    🕒 07:24
22. Remove the dough logs from the freezer and lightly brush them with water. **Key Tip:** If you don't have a brush, you can use your hands to apply the water.
    🕒 07:32
23. Roll the lightly moistened dough logs in the granulated sugar, pressing gently to ensure a good coating. **Key Tip:** Roll the dough firmly enough to ensure the sugar adheres well without causing the cookies to lose their shape.
    🕒 07:48
24. Cut the sugar-coated dough logs into approximately 1cm (0.4 inches) thick slices and arrange them on a baking sheet lined with parchment paper.
    🕒 00:00
25. Bake in the preheated oven at 170°C (340°F) for 16-20 minutes. **Key Tip:** For plain cookies, bake until the edges are lightly browned. For cocoa cookies, bake until the cocoa color deepens.
    🕒 00:00