1. Preheat the oven to 350°F (175°C). Grease a 10×15-inch jelly roll pan and line it with parchment paper. Grease the parchment paper lightly.
2. In a medium bowl, sift together the flour, cocoa powder, baking powder, and salt. Set aside.
3. In a large mixing bowl, beat the eggs and granulated sugar with an electric mixer until light and fluffy, about 5-7 minutes. Add the vanilla extract and mix to combine.
4. Gradually fold in the sifted dry ingredients using a spatula or spoon. Be gentle to maintain the airiness of the batter.
5. Pour the batter into the prepared jelly roll pan and spread it evenly.
6. Bake for 10-12 minutes or until a toothpick inserted into the center comes out clean.
7. As soon as the cake is done, dust a clean kitchen towel with powdered sugar. Turn the cake out onto the towel and remove the parchment paper. Roll the cake with the towel while it’s still hot (this helps prevent cracking) and let it cool completely.

For the Filling:

1. In a large mixing bowl, beat the heavy cream with powdered sugar and vanilla extract until stiff peaks form. Set aside.
2. In another bowl, beat the cream cheese and mascarpone (if using) until smooth and creamy.
3. Gently fold the whipped cream into the cream cheese mixture until combined and smooth.

Assembling the Cake Roll:

1. Once the cake has cooled completely, gently unroll it from the towel.
2. Spread the whipped filling evenly over the entire surface of the cake.
3. Carefully roll the cake back up, starting from one short end.
4. Dust with powdered sugar and, if desired, decorate with chocolate shavings or whipped cream.
5. Refrigerate the cake roll for 30 minutes to set before slicing and serving.