How to cook
First, preheat the oven to 437°F (225°C). Heat the water, milk, butter and salt in a pot on the stove and once they come to a boil, add the sifted flour all at once and stir until the dough begins to separate from the walls and bottom. Remove from the stove and begin adding the eggs one by one while constantly stirring with a wooden spoon. Let the dough cool.
Lay out an oven dish with baking paper and use a pastry bag to form balls the size of a walnut. Smear them with an egg yolk beaten with 1 tablespoon of water and put them to bake for about 20 min. in the middle of the oven - until golden. Then let them cool with the oven door slightly open.
Pierce the profiterole with a knife so that the steam escapes and they cool completely.
For the vanilla sauce, cut the pod into halves, scrape them off and add them along with the beans to the milk in a pot on the stove. Once it comes to a boil, turn off the stove and let cool for 10 min.
Beat the flour with the egg yolks and sugar. Remove the vanilla pod and combine the milk with the egg yolks. Put the cream back on the stove and stir until it thickens. Transfer this cream into bowls and let it cool.
Melt the butter and pour it over the cream to prevent it from cracking and drying. Once the cream cools, stir in the rum. Fill an icing piping syringe or pastry bag with a thin tip with the cream and fill the profiteroles from the bottom. Arrange them in a plate
For the chocolate sauce, crumble the dark chocolate, mix it with 3 tablespoons of water and melt it on the stove. Stir the chocolate mixture with the liquid cream and orange zest. Pour this chocolate sauce over the profiteroles. Optionally you can sprinkle some more orange zest on the very top.