Preheat your oven to 180 °C and line a 40 × 32 cm baking tray with parchment paper.
In a mixing bowl, whip eggs and sugar on high speed with a stand mixer or hand whisk for 6–8 minutes until semi‑stiff.
Reduce speed and gently whisk in sifted plain flour, cocoa powder, and baking powder until smooth.
Pour the batter into the prepared tray and bake for exactly 8 minutes. While the sponge bakes, pit and finely chop the cherries.
Immediately upon removal, place another parchment sheet on the sponge, flip it out of the tray, peel off the bottom sheet, and roll the sponge in fresh parchment; cool completely.
Meanwhile, melt butter, chocolate, and double cream in a microwave‑safe bowl in 30‑second intervals, stirring between cycles, then chill the ganache.
Whisk double cream and icing sugar until soft peaks form and stir in chopped cherries for the filling, and when the ganache is cool, whip it for 3–4 minutes until light and fluffy.
Unroll the cooled sponge, spread the cherry cream evenly, then re‑roll tightly using the parchment.
Finally, use an offset spatula or the back of a spoon to ice the roll with whipped ganache, dust with icing sugar, pipe whipped cream peaks along the top, and garnish each with a cherry.