1. Preheat the oven to 350°F (175°C). Line a jelly roll pan with parchment paper, leaving an overhang on the long sides, and lightly grease the parchment and sides of the pan.

2. In a large bowl, beat the eggs and granulated sugar together with a mixer on high speed until very thick, pale, and tripled in volume; the mixture should fall in a slow ribbon from the whisk. Beat in the vanilla extract.

3. In another bowl, whisk together the flour, cocoa powder, cornstarch, baking powder, and salt. Sift the dry mixture over the whipped eggs in 2 to 3 additions, gently folding with a spatula after each. Drizzle in the milk and fold just until the batter is smooth with no dry streaks.

4. Spread the batter evenly into the prepared pan, smoothing it into the corners. Tap the pan lightly on the counter to release large air bubbles, then bake for 10 to 12 minutes, or until the cake springs back lightly when touched and just pulls away from the edges.

5. While the cake bakes, lay a clean kitchen towel on the counter and dust it generously with powdered sugar. As soon as the cake is done, run a knife around the edges, invert it onto the sugared towel, and carefully peel off the parchment paper.

6. Starting from a short side, roll the warm cake up in the towel into a tight log. Place it seam side down on a rack and let it cool completely in this rolled shape. This helps prevent cracks later.

7. When the cake is cool, pour the cold heavy cream into a chilled bowl. Add the powdered sugar and vanilla, then whip on medium-high speed until medium peaks form. If using, drizzle in the kirsch toward the end of whipping and beat just until combined.

8. Drain the cherries very well and pat them dry with paper towels so they do not water down the filling.

9. Carefully unroll the cooled cake. Brush the inside surface lightly with the cherry syrup or cherry juice, focusing on any drier edges.

10. Spread the whipped cream evenly over the cake, leaving a small 1/2 inch border along the long edges. Scatter the dried cherries evenly over the cream.

11. Starting from the same short side as before, gently roll the cake back up, this time without the towel, using the towel only to help lift and guide the cake if needed. Roll as tightly as you can without squeezing out the filling.

12. Wrap the filled cake roll snugly in plastic wrap and refrigerate for at least 1 hour, or up to overnight, to firm up the cream and set the shape.

13. When ready to serve, unwrap the cake and transfer it to a serving board or platter. Dust the top with powdered sugar, then sprinkle generously with grated dark chocolate or chocolate curls.

14. Pipe or spoon a few small swirls of extra whipped cream on top if desired, and garnish with fresh whole cherries and mint leaves.

15. Slice with a sharp serrated knife using a gentle sawing motion, wiping the blade between cuts for the cleanest spirals. Serve chilled.