For the eggnog cake, grease and flour a cake pan. Preheat the oven to 180°C. Mix all ingredients, except the chocolate icing, well with a hand mixer and add food coloring if desired.
Pour the cake into a 26 cm diameter pan and bake for 45-60 minutes. Use a wooden stick to test if the cake is done. After the eggnog cake has cooled, turn it out, place it on a rack and cover it with the dark chocolate icing.