Put the sifted flour, sugar and a pinch of salt in the bowl of the thermos, mix: 10 sec. speed 4.
Set to speed 4 and pour in the milk slowly, continue for 1 minute.
Add the eggs, mix: 1 min. speed 4, it should result in a smooth and fluid batter.
Pour the mixture into a bowl and seal it with plastic wrap and let the batter rest for about an hour.
After the time has elapsed, add the melted butter to the batter, mixing quickly even with a fork.
Heat a non-stick pan and grease it lightly by rubbing it with a small piece of butter then, off the stove, pour in a meager mixture of batter, making sure that it is distributed evenly.
Put the pan back on the fire and cook the crepe for a couple of minutes, turn it over and after about a minute it's ready.
Set it aside on a plate and continue to prepare the other crepes until the batter is used up.
Fill them as you like... Bon Appetit!
Crepes can be either sweet with a filling of jam or Nutella and sprinkled with icing sugar, or savory stuffed with speck and brie or ham and mozzarella.
I tried to freeze them once cooked and let them cool completely. I put a sheet of parchment paper between one crepes and the other and then closed them in a frost bag. To defrost them, just move them to the fridge and then let them spend a few minutes in a pan.