Chef Christian Thornton serves the cake with caramel ginger ice cream and a berry compote, but for the home cook he suggests an infinitely easier ginger whipped cream: Beat 2 cups chilled heavy cream to soft peaks and fold in 1/4 cup finely chopped crystallized ginger. Its airy softness tempers the intensity of the rich chocolate.
Cook's note:
You can make cake two days ahead and chill, covered. Bring to room temperature before serving.