Combine butter and chocolate in heatproof bowl and melt in the microwave. Stir to combine.
Add sugar, eggs, flour, coconut, and cacao, and stir to combine.
Add pitted cherries and stir to combine.
Pour into a lined rectangular baking pan and bake for 25-30 minutes. Cool on a wire rack.
While the cake cools, make the ganache. Heat the half-and-half in a saucepan until it simmers. Remove from heat, add chocolate and corn syrup, and let sit for 5 minutes. Stir until just combined to avoid splitting.
Spread ganache on the cake and decorate with extra coconut.
Notes
Tip: You need fresh, juicy cherries for a deep cherry flavor and extra moistness, so I would suggest only making this cake when cherries are in season. Frozen cherries won’t work.