In a large bowl sift together all-purpose flour, 3 tablespoons of cocoa powder, and baking powder. This ensures that there are no lumps and gives the cake a smooth texture.
Next, add in the sugar, vanilla, eggs, and vegetable oil. Using a whisk, vigorously combine the ingredients until the mixture is smooth and well blended.
Transfer this luscious batter to a 13 by 18-inch cookie sheet that has been lined with parchment paper. Use an offset spatula to spread the batter evenly across the pan.
Bake the cake in a preheated oven at 350 degrees for 15 to 17 minutes. Keep a close eye on it; the cake should spring back when touched lightly.
Once baked, carefully invert the cake onto a large clean kitchen towel dusted with ¼ cup of cocoa powder. Remove the parchment paper gently.
Roll the cake up in the towel, starting from one short end, and let it cool completely at room temperature for about 2 to 2 and a half hours.
While the cake is cooling, prepare the filling. In a separate bowl, whisk together heavy whipping cream, powdered sugar, vanilla, and cocoa powder. Whip until medium-stiff peaks form.
Next, fold in the mascarpone cheese until the mixture reaches stiff peaks. This will create a rich and creamy filling.
Prepare the ganache and any additional decorations like sugared cranberries, sugared rosemary, and meringue mushrooms.
Once the cake has fully cooled, gently unroll it. Spread the creamy mascarpone whipped cream filling evenly from edge to edge.
Carefully roll the cake back up, ensuring the filling doesn’t spill out of the edges. Wrap the rolled cake tightly in plastic wrap and chill it in the refrigerator for about 30 minutes.
When ready to serve, slice the cake at an angle to create a log-like appearance. Use some ganache or leftover whipped cream filling to attach the cut piece to the side of the cake.
Spread the ganache generously all over the top and sides of the Christmas Yule Log Cake, leaving the cut ends exposed for a rustic look.
