Bring cream just to a boil, stirring occasionally, in a small saucepan over medium heat; remove from heat. Put chocolate in a medium heatproof bowl, and pour cream on top; let stand 5 minutes. Gently stir until ganache is smooth and glossy.Advertisement
Transfer 3/4 cup ganache to another bowl. Refrigerate all ganache, stirring occasionally, until slightly cooled and thickened, about 10 minutes (do not let it harden). Meanwhile, cook cherry liquid in a small saucepan over medium-low heat until reduced by half, about 10 minutes; set aside, covered, until ready to assemble cake.
Set aside reserved 3/4 cup ganache for coating tiers; gently fold drained chopped cherries into remainder. Let all the ganache stand at room temperature, stirring occasionally until spreadable.