1. Prepare the Sponge Cake:

1. Preheat oven to 350°F (175°C). Line a 10×15-inch jelly roll pan with parchment paper.
2. Beat eggs and granulated sugar on high speed for 5–7 minutes until pale, thick, and tripled in volume. Mix in vanilla extract.
3. Sift flour, cocoa powder, baking powder, and salt together. Gently fold into the egg mixture.
4. Pour the batter into the pan, spreading evenly. Bake for 10–12 minutes until the top springs back when lightly touched.
5. Lay a clean kitchen towel on a surface and dust with powdered sugar.

2. Roll the Cake:

1. Invert the cake onto the towel and peel off the parchment paper.
2. Starting from the short edge, gently roll the cake (with the towel) into a tight spiral. Let it cool completely.

3. Make the Filling:

1. Whip heavy cream, powdered sugar, cocoa powder, and vanilla until stiff peaks form.
2. Carefully unroll the cooled cake and spread the filling evenly, leaving a ½-inch border.

4. Roll and Chill:

1. Re-roll the cake tightly without the towel.
2. Wrap in plastic wrap and refrigerate for at least 2 hours.

5. Prepare the Ganache:

1. Heat heavy cream until it begins to simmer.
2. Pour over chocolate chips in a bowl and let sit for 2–3 minutes. Stir until smooth.
3. Add butter for extra shine.

6. Assemble and Decorate:

1. Place the chilled Swiss roll on a serving platter.
2. Pour the ganache over the roll, letting it drip down the sides.
3. Decorate with chocolate shavings, berries, or edible gold leaf.
4. Chill for 30 minutes before slicing.