Preheat the oven to 374º F (190°C). Line a 17 x 12 inches (43cm x 30cm) rectangular cake pan with parchment paper and some butter.
Sift together the flour, cocoa, baking powder and salt in a medium bowl.
Separate the eggs and place the egg whites in a large clean, dry bowl and the yolks in another large bowl.
With an electric mixer or a hand whisk, beat the egg whites for 30 seconds until slightly fluffy, gradually add half the sugar and continue beating for a 2 more minutes until the mixture turns white and foamy and stiff peaks form. Set aside until needed.
Separately, with the same mixer, beat the egg yolks with the rest of the sugar for 2 minutes until the mixture is fluffy and slightly lightens in color.
Add the melted butter, espresso, vanilla extract and continue beating for 1 more minute until smooth.
Add the flour mixture and beat for 30 seconds just until smooth.
Finally, add the beaten egg whites in three separate additions, mixing with a rubber spatula carefully, in an folding motion until fully integrated.
Pour this mixture into the cake pan and spread over the entire surface with the same spatula to even it out. Bake in the upper part of the oven for 10-12 minutes until done.
Place a piece of parchment paper (slightly larger than the cake tin) on the kitchen counter and spread the 2 tablespoons of cocoa powder on it. Once out of the oven and still a little warm, turn the sponge cake out onto the parchment paper, roll it up on itself (with the paper and all) widthwise and leave it to cool down rolled up for at least 30 minutes or it can be refrigerated for up to 1 day.
For the cream filling:
Place a medium saucepan over medium heat. Add the marshmallows with the milk and cook, stirring constantly, for about 2-3 minutes until the marshmallows are completely melted.
Pour the marshmallow mixture into a large bowl, add the icing sugar, vanilla extract, and salt and mix with a hand whisk until smooth. Let it sit to cool down completely.
Add the cream cheese to the same bowl and beat with an electric mixer for 1 minute until smooth and homogeneous. Add the whipping cream and beat for another 4-5 minutes until stiff peaks form. It is important not to overmix.
To assemble:
Once the sponge cake is cool and has taken shape, unroll it and remove the parchment paper. Add all the filling and spread it evenly with a rubber spatula.
Roll again widthwise until a tightly closed roll is formed. Wrap in plastuc film wrap and refrigerate for at least 30 minutes or up to 3 hours.
To make the chocolate ganache to decorate the roll, place the chocolate chips with the whipping cream in a bowl and melt in the microwave for 30-second intervals, i.e. put it in the microwave for 30 seconds and take it out after this time to mix a little with a fork. Repeat the process until the chocolate is completely melted (this prevents it from burning).
Remove the roll from the refrigerator, place it on a wire rack with a baking sheet underneath and glaze it with the ganache until it is completely covered. The baking sheet under the rack is used to catch the chocolate that falls when the roll is being glazed.
Refrigerate the chocolate roll again for at least 30 minutes. Once ready, cut off the ends to make it more presentable, and it is ready to serve.