Combine the finely chopped chocolate and heavy cream in a microwave-safe bowl. Heat for 1 minute at 100% power in the microwave. Let stand for 1 minute and then whisk together until smooth. Add the champagne and whisk again until combined. Place to set.
Meanwhile, split the cherries horizontally and twist to open, leaving stems intact. Remove the pits by twisting them with your fingers (discard pits). Pat the cherry flesh dry on paper towels and transfer them to a zip top bag lined with paper towels to absorb any cherry juice that may seep from the cut cherries. If cherries want to roll and not stand upright, slice a tiny sliver from the cherry bottoms so they will sit flat. It’s best to do this before the cherries are filled.
Beat ganache on high speed for 3 minutes, or until the mixture is thick like buttercream and pipeable. Transfer the ganache to a piping bag fitted with a small closed star tip.
Fill the cherries. Finish by sandwiching with a cherry top. Repeat with remaining cherries and ganache.