Preparing the Cake

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Line a 15×10-inch jelly roll pan with parchment paper, ensuring that it fits snugly into the corners of the pan.
2. Whisk the Eggs and Sugar: In a large bowl, whisk together the eggs and granulated sugar using a hand mixer or stand mixer. Beat for 5-7 minutes until the mixture becomes pale and fluffy.
3. Add Vanilla and Dry Ingredients: Add the vanilla extract to the egg mixture. In a separate bowl, sift together the cocoa powder, baking powder, salt, and flour. Gently fold the dry ingredients into the egg mixture using a spatula. Be careful not to deflate the batter.
4. Spread the Batter: Pour the batter into the prepared jelly roll pan, spreading it evenly with a spatula.
5. Bake the Cake: Bake the cake for 12-15 minutes, or until it springs back when lightly touched. A toothpick inserted in the center should come out clean.
6. Cool the Cake: Once the cake is done, remove it from the oven and allow it to cool for about 10 minutes in the pan. Then, carefully invert the cake onto a clean kitchen towel dusted with powdered sugar. Peel off the parchment paper and let the cake cool completely.

Prepare the Filling

7. Whip the Cream: In a chilled bowl, whip the heavy cream, powdered sugar, and vanilla extract until stiff peaks form. This should take about 3-4 minutes using an electric mixer.
8. Set Aside: Once whipped, set the cream aside in the refrigerator while you prepare the frosting.

Make the Chocolate Buttercream

9. Beat the Butter: In a separate bowl, beat the softened butter until creamy and light. This should take about 3-4 minutes with an electric mixer.
10. Add Cocoa Powder and Powdered Sugar: Gradually sift in the cocoa powder and powdered sugar, continuing to beat the mixture until smooth.
11. Add Milk and Vanilla: Add the milk (a little at a time) to reach a spreadable consistency. Stir in the vanilla extract and a pinch of salt. Continue beating until the frosting is smooth and fluffy.

Assemble

12. Roll the Cake: Once the cake has cooled completely, carefully unroll it from the towel. Spread a layer of whipped cream filling evenly over the cake, leaving about an inch of space at the edges.
13. Re-roll the Cake: Starting from one short side, carefully roll the cake back up with the cream filling inside. Be gentle to avoid cracking the cake.
14. Frost the Cake: Place the rolled cake onto a serving platter. Cover the entire cake with the chocolate buttercream, smoothing the frosting with a spatula.
15. Create the Log Effect: Using a fork or a serrated knife, create texture in the frosting to mimic the appearance of tree bark. You can also add some extra details such as “branches” or a stump at the end of the log for an added effect.

Decorate

16. Add Decorations: Dust the top of the Yule Log with powdered sugar to resemble snow. You can also decorate with marzipan mushrooms, berries, or a sprig of holly for a festive touch.
17. Chill the Cake: Chill the Yule Log Cake in the refrigerator for at least an hour to allow the buttercream to set and make slicing easier.

Slice and Serve

18. Serve: Once chilled and set, slice the Yule Log Cake into portions and serve to your guests. Enjoy the rich chocolate flavor and the creamy filling with every bite!