Preheat oven to 350°F (175°C). Line a 10×15-inch jelly roll pan with parchment paper and lightly grease.

Beat eggs and granulated sugar until pale, thick, and fluffy. Stir in vanilla extract.

Sift flour, cocoa powder, baking powder, and salt together. Gently fold into egg mixture.

Spread batter evenly in prepared pan and bake for 10–12 minutes, until cake springs back lightly when touched.

Immediately turn cake onto a powdered sugar–dusted kitchen towel. Remove parchment paper and roll cake (with towel) from the short end. Let cool completely.

Beat heavy cream, powdered sugar, and vanilla until stiff peaks form. Fold in kirsch or cherry juice if using.

Unroll cooled cake and spread whipped cream evenly, leaving a small border. Sprinkle cherries over the cream.

Carefully roll cake back up and place seam-side down on a serving platter.

Heat heavy cream until just simmering. Pour over chopped chocolate and butter. Let sit 1 minute, then stir until smooth.

Drizzle ganache over cake roll. Garnish with whipped cream, cherries, and chocolate shavings.

Chill for 30 minutes before slicing and serving.