Preheat the oven and grease a baking pan that is not too small and not too large. Beat the eggs and sugar together until light and foamy. Add the milk and melted butter, then mix well. Add the flour, cocoa powder, and baking powder, and stir until combined.

Pour the batter into the prepared pan and bake until a toothpick comes out clean with no crumbs. The cake should be fully baked but still soft.

While the cake is baking or shortly before it finishes, combine oil, sugar, cocoa powder, milk, vanilla extract, and a pinch of salt in a saucepan. Cook until smooth and slightly thickened.

As soon as the cake comes out of the oven, pour the hot sauce evenly over the warm cake. Let it soak in fully.

Heat the cream until very hot, then pour it over the chopped chocolate. Let it sit for a moment, then stir until completely smooth and glossy.

Spread the second chocolate layer over the cooled cake. Add your decoration of choice while the chocolate is still soft.

Let the cake rest before slicing, then serve and enjoy.