Preheat your oven to 375°F (190°C) and line a 10x15 jelly roll pan with parchment paper.

Beat the egg whites in a mixing bowl until stiff peaks form, about 3-5 minutes.

In another bowl, beat together egg yolks and granulated sugar until thick and pale, about 5 minutes, then mix in vanilla extract.

Sift together cocoa powder, flour, baking powder, and salt. Fold this into the egg yolk mixture gently.

Gently fold in the egg whites until no streaks remain.

Spread the batter evenly in the pan and bake for 12-15 minutes until springy.

Dust a clean kitchen towel with powdered sugar, flip the baked cake onto it, and roll it up gently.

Cool the rolled cake seam-side down for 30-40 minutes.

Whip together the cold heavy cream, powdered sugar, and vanilla until stiff, then fold in cherry pie filling and maraschino cherries.

Unroll the cooled cake and spread the cherry filling evenly over it, leaving a 1-inch border.

Roll the cake back up tightly without the towel, seam-side down on a platter.

If using, bloom the gelatin in cold water for 5 minutes, then melt and mix with whipped cream.

Cover the roll with the remaining whipped cream and smooth the surface.

Decorate with piped rosettes, cherries, chocolate curls, syrup, and optional cocoa powder.

Chill the cake roll in the refrigerator for at least 1 hour before slicing.