Preheat oven to 325 degrees F (160 celsius) Fahrenheit) and grease an 8" (20 cm) spring form pan.
Place the butter and sugar in the bowl of an electric mixer fitted with a paddle attachment and beat until light and creamy.
Gradually add the eggs and beat well between each addition.
Fold through the flour, cocoa, baking powder and milk until combined.
Scatter the cherries through the cake mixture and fold through. Pour the mixture into the prepared baking pan and bake for 55 to 60 minutes or until cooked when tested with a skewer. Let the cake rest in the pan for 10 minutes before placing on a wire rack to cool.
To make the chocolate ganache place the cream and chocolate in a saucepan over a low heat until melted and smooth. Set aside and let it come to room temperature.
To make the chocolate shards collect some parchment paper, a spatula and a ruler (or something similarly flat). Place 1 large sheet of baking paper on the kitchen bench and pour the melted chocolate over the top. (You can melt the chocolate in a double boiler, or just in the microwave.) Smooth with a spatula and cover with another sheet of parchment paper. Use the side of the ruler to smooth out the chocolate to a smooth even layer, leaving a 2cm border at the edge. Carefully roll the parchment paper into a roll and place into the refrigerator to set.
Cut the cake in half (so you have a top and bottom layer) and drizzle each half of the cake with the reserved cherry syrup. Note I used only half of the syrup, but it's up to you how much you use. Leave the cakes for 30 minute to allow the syrup to soak into the cake.
To assemble the cake, spread ganache over the bottom half of the cake before topping with the top of the cake. Cover the outside of the cake with the ganache, using an angled spatula. Remove the chocolate from the refrigerator and unroll. This will crack the chocolate into shards. Arrange the shards around the cake, pressing into the ganache to secure.
Serve with whipped cream.
Donna's recipe included adding a layer of cream between the layers of cake. I prefer to serve whipped cream on the side.