Steps

1. Prepare the template.
   🕒 00:53
2. Prepare the double boiler. Turn off the heat once the water is warm.
   🕒 00:53
3. Warm 25g milk and 10g rice oil in the microwave for 20-30 seconds.
   🕒 00:56
4. Preheat the oven to 180°C (350°F).
   🕒 01:02
5. Mix 50g all-purpose flour and 15g cocoa powder well, then sift.
   🕒 01:13
6. Whisk 3 whole eggs well, add 70g granulated sugar, and warm over a double boiler until lukewarm.
   🕒 01:23
7. Remove from the double boiler and whisk on high speed until the batter turns pale and the lines from the whisk no longer disappear. (This is the key!) Whisk while rotating the mixer to incorporate air evenly. Whisk until you feel no more air can be incorporated.
   🕒 01:33
8. Reduce the mixer speed to low and beat for about 2 minutes to refine the batter's texture. (This is the key!) This will result in a smoother texture and a more stable bake. Beat until glossy.
   🕒 02:22
9. Add the sifted flour and cocoa powder all at once and mix by scooping from the bottom until no lumps remain. Rotate the bowl while mixing to ensure even incorporation.
   🕒 02:53
10. Take a portion of the batter and mix it into the bowl with the warmed milk and rice oil. Mix thoroughly. (This is the key!) If the milk and oil have cooled, gently warm them again to mix more easily.
    🕒 03:37
11. Return the mixed milk and rice oil mixture to the rest of the batter and mix until uniformly combined.
    🕒 03:58
12. Pour the batter onto a baking sheet and spread evenly with a rubber spatula or scraper.
    🕒 04:22
13. Gently shake the baking sheet side to side and tap it down to level the batter.
    🕒 04:41
14. Bake for 11 minutes in the preheated oven at 180°C (350°F). (This is the key!) Insert a skewer; if it comes out clean, it's done.
    🕒 04:51
15. Immediately after baking, tap the sheet from above and transfer the cake to a wire rack.
    🕒 05:05
16. Remove the parchment paper from the edges to prevent shrinking.
    🕒 05:10
17. Once cooled slightly, cover lightly with plastic wrap to prevent drying and let it cool completely.
    🕒 05:17
18. Finely chop 80g sweet chocolate.
    🕒 05:36
19. Gently warm 80g heavy cream for the ganache until small bubbles form around the edges.
    🕒 06:00
20. Pour the warm heavy cream all at once over the chopped chocolate. Do not stir immediately; let it sit for a moment, then start mixing from the center. (This is the key!) If some chocolate remains unmelted, microwave for a few tens of seconds.
    🕒 06:10
21. Let the prepared ganache sit at room temperature.
    🕒 06:30
22. Whip 240g heavy cream and 20g granulated sugar over an ice bath. Stop when soft peaks form (when you lift the whisk, a light line appears).
    🕒 06:34
23. Add a portion of the whipped heavy cream to the ganache and mix thoroughly.
    🕒 07:03
24. Combine with the remaining whipped heavy cream to create the chocolate cream.
    🕒 07:20
25. Lightly chop 30-40g roasted walnuts.
    🕒 07:32
26. Invert the cooled cake onto parchment paper, remove the paper, and invert it back.
    🕒 07:57
27. Spread the chocolate cream evenly over the entire surface of the cake. (This is the key!) Whip the cream for the filling more firmly (it should not fall off the whisk).
    🕒 08:17
28. Sprinkle the chopped walnuts evenly over the cream and gently press them down to prevent them from shifting when rolling.
    🕒 08:52
29. To create the core of the roll, lift the edge of the cake closest to you and press down with a ruler or similar tool to form a core. Once the core is formed, continue rolling the cake while holding the core, up to the end of the cream. (This is the key!) The parchment paper can be slippery; hold it down with one hand for easier rolling.
    🕒 09:02
30. If the roll is loose, hold down the bottom paper and firmly pull towards you with a ruler or similar tool to tighten. Position the seam on the bottom and let it rest in the refrigerator.
    🕒 09:43