In a bowl, beat the eggs with the sugar for the cake until creamy, pour in the oil in a thin trickle and the milk.
Pour the egg mixture into the flour and other dry ingredients. Stir to a homogeneous cocoa mixture.
Smear an oven dish with a little oil, sprinkle with flour, pour in the cake mixture and put it in the oven.
Heat to 356°F (180 °C), then bake the cake 40 min. until a toothpick comes out dry when you poke it. Take it out and leave it to cool.
In the meantime, make the cream by beating the yolks with the sugar in a bowl until it becomes a creamy mixture, add the flour and starch and stir very well until you get a sludge.
Heat the milk a little and pour it carefully into the yolk mixture, stir. Pour the mixture into a pot and put it on the stove. Heat it up, once it starts to boil it will begin to thicken. At that point, start to beat nonstop energetically until you get a thick cream. Turn the stove off, add the butter and vanilla. Stir and leave the cream to cool.
Take a small shot glass or small ring. Use it to make holes in the cake, some distance apart. Dig out the resulting holes and remove their insides.
Leave these cake pieces aside, fill the holes with the cream. Pour the rest of the cream over the cake and even it out. Crumble the cake pieces over the cream and grate the chocolate.
Leave the cake for a few hours to cool.