Preheat your oven to 350°F and line a jelly roll pan with parchment paper. In a large bowl, whisk together the cake flour, sifted cocoa powder, baking powder, espresso powder, and 1/4 teaspoon of salt. In a separate bowl, whip the room temperature eggs until light and foamy, then gradually add the granulated sugar and 1 teaspoon of vanilla extract, continuing to whip until the mixture is thick and pale. Gently fold half of the dry ingredient mix into the egg mixture, then fold in the remaining dry ingredients until just combined without overmixing. Pour the batter evenly onto the prepared pan and bake for 10-12 minutes, or until a toothpick inserted into the center comes out clean. I like to ensure my eggs are at room temperature for maximum volume and a lighter cake.

While the cake is still warm, carefully invert it onto a clean kitchen towel dusted lightly with confectioners' sugar. Gently peel off the parchment paper. Starting from one short end, roll the cake tightly along with the towel. Let the rolled cake cool completely at room temperature; this step is crucial for preventing cracks later on when you unroll and fill it. I typically leave it to cool for at least an hour to ensure it's fully set.

Finely chop the bittersweet chocolate and place it in a heatproof bowl with the melted unsalted butter, 1 teaspoon of vanilla extract, and a pinch of salt. In a small saucepan, warm the 3/4 cup of heavy cream over medium heat until it just begins to simmer around the edges; do not boil. Pour the hot cream over the chocolate mixture, let it sit for 5 minutes, then stir gently from the center outwards until completely smooth and glossy. Set aside to cool to room temperature until it thickens to a spreadable consistency; if it's too warm, it will melt your whipped cream.

In a chilled bowl, combine the cold heavy cream, 1 teaspoon of vanilla extract, and the remaining 1/4 cup of sifted confectioners' sugar. Whip with an electric mixer on medium-high speed until firm peaks form. Be careful not to over-whip, as it can quickly turn grainy. This will be the light and airy filling for your cake roll.

Once the cake is completely cool, carefully unroll it. Evenly spread the whipped cream filling over the entire surface, leaving about a 1-inch border clear at one short end. Tightly re-roll the cake, starting from the short end with the cream all the way to the uncreamed edge. Transfer the rolled cake to a serving platter. If desired, cut a small piece off one end at an angle and attach it to the side of the log with a little ganache to create a 'branch'. Finally, spread the cooled chocolate ganache all over the cake, covering it completely. Use a fork or toothpick to create a wood-grain texture, then chill until the ganache is set before garnishing and serving. For a truly professional finish, I always ensure my ganache is the perfect temperature for spreading—not too hot to melt the cream, and not too cold to be unmanageable.