Put the milk, eggs, flour, yeast and salt in a bowl.
Beat everything together until you have a thick cream and leave to rest (at least a couple of hours at room temperature).
Heat the griddle.
When it is very hot, cover the bottom with a little of the cream, let it fry on one side and as soon as it is done, turn it over to fry on the other side (maximum 1 minute).
When they are fried, sprinkle with sugar.
You can also add jam, cream, cream, chocolate...
These are the sweet frixuelos, but if you remove the sugar, you can fill them with anything savoury you can think of: cheese, prawns, mushrooms...