Preheat the oven to 350 degrees F.

Make the chocolate cake according to the directions on the box.

Pour into a well greased, round/rectangle ovenproof dish.

The cake mixture should not go more than halfway up the sides of the dish, as the melted chocolate liquid still has to be poured over the cake batter before baking.

Melt the chocolate over boiling water, like a double boiler. 

Pour the chocolate liquid evenly over the cake batter and bake for 45 minutes.

It will still look uncooked and soft on the top, but this is a self-basting pudding (makes its own sauce) and needs to have this sauce.

Serve warm with vanilla ice cream.