It is said that profiteroles are difficult to make. This is not true.
It is actually very easy, but you do have to follow the directions exactly!

Basic Profiteroles Dough:
1/4 l water
1/3 ts salt
100 gr butter
150 gr white flour
4 eggs
1 ts baking powder

If you want to put a sweet filling, you can add 1 packet vanillin sugar with the salt.

Preparation:

Boil the water with the salt. Add the butter and stir until it is all melted.
Empty the flour all at once in the still boiling water, while stirring steadily. Keep stirring on medium heat, until the dough forms one solid lump.
Keep stirring and “burn” the dough dumpling from all sides, until the bottom of the pan is covered with a thin white layer.
Than put the hot dough in a clean cold jar and, while kneading with an electric mixer, add the eggs one by one. Always mix one egg completely under before adding the next!!!
In the very end, when the dough is already cool, mix the baking powder under.

Oil a baking sheet very well and sprinkle it with flour.
Put on it with a spoon small lumps of dough, app. 10 pieces. Leave enough space in between them, they grow to double or triple size while baking!
Bake in the preheated oven (around 200 degree) for 25 to 35 minutes until golden brown. Do not open the oven door during the first 15 minutes!!!
Cut the top of the profiteroles off with a scissor immediately after they come out of the oven.
Leave them to cool and fill the base as you like: with custard cream, or vanillin pudding or custard cream and fruits, or whipped cream, or whatever idea you have, than put the cover back on top and sprinkle with powdered sugar.
Or fill with anchovies cream or other salty filling.

Important tips and tricks for making profiteroles:

Never work with “eye measure”. Always take the exact amount of all ingredients as it written.
Boil the water quickly with the lid closed ant than add the flour immediately or too much of the water evaporates and the amount is not correct anymore. Always add the flour quickly and in one go, if you add it one by one, you not get one big smooth ‘dumpling’, but a lumpy mess. Stir the dough constantly on medium heat, until the dumpling forms and the bottom of the pan gets covered with a thin white layer of dough. Move the hot dough in a cold pan, before adding the eggs, or they will clot.
Add the eggs one by one and watch the dough: If you got big eggs,the last egg might be already too much. The finished dough must be glistening and form firm tips, if you take a spoon out. The amount of eggs is correct, if the dough is really glossy and falls from the spoon in a way that long “spikes” keep hanging. Add the baking powder only at last, when the dough is cool. Always preheat the oven well, and NEVER open the oven in the first half of the baking time. Otherwise the dough will collapse immediately! The dough should be processed in one go, you should bake it just after you finished kneading it. But you can put the ready dough in the freezer for later baking, or you can deep-freeze the baked, but yet unfilled profiteroles.
Profiteroles should be eaten soon after baking, or they lose their crispiness (specially when filled).