In a big bowl (or in the bowl of an electric mixer) place the water along with the evaporated milk, half of the sugar and yeast and let it rest for 10 minutes.
Once this time has passed, add in the rest of the sugar, eggs, vanilla extract and mix well with a fork until integrated.
Add in the sifted flour, salt and powdered milk and mix using the same fork for 1 minute until you get a sticky dough.
Place the dough on a clean surface and knead for 7 minutes by folding it onto itself. Integrate the butter little by little until completely smooth, about 3 minutes. At first it will seem hard but it will intergrate.
Knead for 3 minutes until you get a soft elastic dough. This whole porcess can also be done using a mixer with the dough hook on.
Place the dough in a greased (with some oil) bowl and cover it with plastic kitchen wrap or a kitchen towel and let it rest for an hour and a half in a warm spot.
For the pastry cream:
In a small pot over low heat, pour the milk along with half the sugar, the vanilla bean seeds and cook for 1 minute, mixing occasionally with a hand whisk.
In a small bowl, mix the rest of the sugar with the salt, egg yolks and corn starch. Add a little of the milk mixture and beat to make this egg mixture warm.
Pour the egg yolk mixture into the milk pot and cook over medium heat for 3 minutes aprox, beating non stop, until a thick mixture forms.
Take off the heat and beat and stir in the butter. Pour the pastry cream into a different bowl, cover it with plastic kitchen wrap (the plastic must touch the cream surface so that it doesn´t set on the top) and refrigerate for 1 hour.
To make the berliners:
Once the dough has doubled in size, place it on a clean floured surface and roll it out until it is 1/3 inch (7 mm) thick. Cut out circles of about 2.8 inches (7 cm) and place them on a baking sheet lined with parchment paper so that they don´t stick to it. Repeat this just once more rolling out the remaining dough and make tiny circles with the leftover dough at the end.
Cover the berliners with a kitchen towel and let then rest for 30 minutes. Pour enough quantity of vegetable oil in a medium size pot over low heat. It is important for the oil not to be too hot so that the berliners can cook thoroughly.
Once the oil is hot, fry the berliners three at a time, or two, depending on the size of the pot. They have to cook for about 2 to 3 minutes on each side. Place them on a plate lined with some kitchen paper so it absorbs the excess oil and let them cool before filling.
Once cool, cut a little the berliners on the sides (as if cutting them in half but not completely). Put the pastry cream in a pipping bag with a star shaped nozzle and fill the berliners with enough cream, trying to make them look cute on the edge.
Sprinkle some confectioners sugar on top and they´re ready!