Adding fruit to cake recipes makes a rich, interesting variation on old-fashioned chocolate cake. Orange juice adds sweetness and orange rind adds a bit more complexity. This cake makes a wonderful dessert for almost any occasion, as it can be elegantly frosted for special events or simply eaten plain for an everyday dessert.
Preheat the oven to 191 degrees Celsius. Grease an 8-inch cake pan with butter.
Beat the sugar and butter with an electric mixer in a large mixing bowl until the mixture becomes light and airy. Add the eggs one at a time and continue beating the mixture.
Fold in the sifted flour slowly, mixing by hand or at low-speed continuously.
Divide the mixture into two bowls. Add the cocoa and milk to one bowl and mix by hand. Add the orange juice and orange rind to the other bowl.
Add the contents of both bowls to the cake pan, swirling with the tines of a fork to create a marbled effect.
Bake at 375F for 25-30 minutes.
Allow the cake to cool for 10 minutes in the pan and then transfer to a wire cooling rack for 10 to 15 minutes before topping with your favourite frosting. Serve warm.
Add a touch of lemon juice for a fruitier, less sweet flavour.