Melt the butter in a pan, add the flour and braise it. Carefully add the milk cup by cup and let it come to a boil.
Then cool the mixture, add 1/2 cup (120 g) of sugar, the cocoa and vanilla. Mix everything well. Whip the egg yolks with the remaining sugar, whip the egg whites to snow with a pinch of salt and add them to the milk blend.
Pour out the resulting dough in buttered forms and briefly bake in a water bath in a hot oven. Serve with the glaze.
To make the glaze: Beat the egg yolks with a mixer. Add the sugar, flour and 4/5 cup (200 mL) of the milk.
Stir until you get a homogeneous mixture and pour it while stirring in the remaining boiling milk. At the end, add the cocoa and rum.