It is a dessert. But it can be breakfast, when you don´t feel like porridge, lots of grains. I like it less sweet and darker and eaten with jam it doesn´t need to be too sweet, but it is your choice if you want more sugar.
dissolve cocoa powder in a small amount of milk. do the same with potato or corn flour, separately. Add the rest of the milk to cocoa, bring to boil. Remove from heat. add sugar and vanilla sugar (I do it away from heat cause adding sugar right away may cause the milk to burn more easy). then add the flour, place back on the heat and stir until thickened and smooth.
let cool in before serving, if it formes a skin during that, remove it before pouring into a ceramic or glass bowl and topping with jam and cookies.
similar dessert can be made without cocoa just from milk, vanilla and flour.